Dark Heresy: The Movie

By Lightbringer, in Dark Heresy

OK, here's a thought for a dull afternoon. Due to your incredible screenwriting abilities and clout in Hollywood, as well as your fanatical love of Dark Heresy, you are called into the offices of a top Movie Mogul

Sitting opposite you, gazing across the expanse of his vast, shiny desk, puffing on a cigar and playing idly with an executive toy, he instructs you to make the opening movie in a 3-part trilogy set entirely within the Imperium of man, the first of an epic Warhammer 40k series. He tells you that you have a budget of $200 million (for special effects, stars etc) and that if the film makes over $500 million, you'll get 5% of the gross profits. And get to direct the sequels.

As you stagger home, dazed by the awesome responsibility on your shoulders, your mouth dry at the thought of finally having the funds to buy an original DH Collector's edition on ebay, you slowly start to wonder about how you'd go about it...

What would you feature in the screenplay? What's the plot?

How would you explain the incredibly complex Imperium to total novices using a practically infinite budget?

What action/set pieces would you employ?

What stars do you cast, if any?

What do you save for the sequels?

How do you avoid either the movie or the trilogy sucking completely?

Any thoughts?

Lightbringer said:

What would you feature in the screenplay? What's the plot?

How would you explain the incredibly complex Imperium to total novices using a practically infinite budget?

What action/set pieces would you employ?

What stars do you cast, if any?

What do you save for the sequels?

How do you avoid either the movie or the trilogy sucking completely?

Any thoughts?

Hmmm. I would have gone with a TV series instead, personally, but ok. Interesting in the context of their decision to go with an Ultramarines movie for #1.

I think first step is to hire Abnett to screenplay either Eisenhorn or Ravenor. To me, I think you need the humanness and flexibility of the Inquisition to pull people in, and those two series are unusual within 40k fiction for combining some really great action, characters with some real depth to them who really go through some character development, and plot that's very pulp-like in that it's not just fight-sequences but is also very cliffhangery even if explosions aren't going off at the moment.

I think with the Imperium, the quickest way to explain things is to have the action feature at least three planets - one hive, one feudal, and one feral - to show the diversity of the Imperium, that you can go from Bladerunner to Mad Max very quickly. I also think that Inquisition-based plots, like those discussed above are best, because you get a good picture of the different Imperial institutions, how much they conflict with each other, etc.

Set pieces - just from memory, in the Ravenor series, that epic gunfight out in Lucky Space where everything goes horribly wrong and then the heroes have to fight their way out of sudden death, the Mission: Impossible sequence where the team infiltrates the Admin building, the birth of Slyte/assault on the cathedral, and the stormy conclusion in the traitor's citadel. In Eisenhorn, I'd definitely include the failed infiltration of House Glaw, the standoff between Eisenhorn and the conspirators on Gilian's Acre, the Purge of KCX-1288, the Thracian Atrocity, the epic battle with Cherubael, Prophaniti and Quixos on Farness Beta, etc.

Lightbringer said:

OK, here's a thought for a dull afternoon. Due to your incredible screenwriting abilities and clout in Hollywood, as well as your fanatical love of Dark Heresy, you are called into the offices of a top Movie Mogul

Sitting opposite you, gazing across the expanse of his vast, shiny desk, puffing on a cigar and playing idly with an executive toy, he instructs you to make the opening movie in a 3-part trilogy set entirely within the Imperium of man, the first of an epic Warhammer 40k series. He tells you that you have a budget of $200 million (for special effects, stars etc) and that if the film makes over $500 million, you'll get 5% of the gross profits. And get to direct the sequels.

As you stagger home, dazed by the awesome responsibility on your shoulders, your mouth dry at the thought of finally having the funds to buy an original DH Collector's edition on ebay, you slowly start to wonder about how you'd go about it...

What would you feature in the screenplay? What's the plot?

How would you explain the incredibly complex Imperium to total novices using a practically infinite budget?

What action/set pieces would you employ?

What stars do you cast, if any?

What do you save for the sequels?

How do you avoid either the movie or the trilogy sucking completely?

Any thoughts?

So, this is to be a big holywood block-buster then? In that case:

What would you feature in the screenplay? What's the plot?

The screenplay is easy. In fact, it pretty much writes it self. Imperium bad, freedom good. A dashing 20 something hero, wait, scratch that. A beautiful 20 something strong woman heroine with a great rack who doesn't quite fit into the evil Imperium realizes how evil it is. Then there's some killing, she takes a shower, a cute 20 something guy on the wrong side is won over by her and together they make a really big explosion. Happy ending! The rest like diolog and all that can just be hammered out in a night or so or taped together from other screenplays.

It would have the fallowing teaser tagline:

  • In an empire of insanity and barbarism, a lawman and a cleric combat an army of fallen angels.

or possibly any of these... they're all good...

  • On a planet of barbarism and fear, a computer techician seeks the ultimate weapon and fights evil.
  • In a universe of lost souls, an occultist and a thief seek vengance and battle evil.
  • On a damned planet of blasphemy, a computer techician and a cyborg oppose crime.
  • In a world of lies and virutal reality, in an era of suffering and pain, a demon and a heroine try to find justice and oppose crime.
  • In a city of agony, in an era of illusion, six linguists try to find an ancient artifact.
  • In an amazing empire of blood, in an era of war, a rogue and a chemist seek hope and battle evil.
  • On an evil world of warfare, three hunters and a gladiator battle evil.
  • On a planet of sorcery, in a time of danger and technology, a singer tries to save the last living fertile woman.
  • On a barbaric planet, four jailers and a wanderer try to prevent the apocalypse.
  • In a universe of confusion and terror, in a time of misery and deception, eight nobles hope to stop the apocalypse.

These tag-line summaries were created the same way Hollywood producers do it (judging by watching their movies) -by using THIS.

The final touch to this stage would be it's name, which is, quite possibly, the most important step. Now, I'm just tossing this out there but what about...; Star Wars? It already has a built in audience and so the profits are almost guaranteed and lets face it, it's old, over the hill, it needs to be remade. A perfect project for investors to get behind. If we fail to get the rights to that, then perhaps Herbie the Love Bug.

How would you explain the incredibly complex Imperium to total novices using a practically infinite budget?

Easy, with scrolling words at the beginning of the feature. Studies show that popular movies which become well loved classics have employed this technique. It would start "IT IS THE 41st millennium. For more than a hundred centuries the Emperor has sat immobile on the Golden Throne of Earth. He is the master of mankind by the will of the gods..."

What action/set pieces would you employ?

Big ships in the void with EXPLOSIONS; massive sprawling city-hives with red skies and pumping noxious clouds that the camera swoops around and through in exciting ways to fill up some of the plot before more EXPLOSIONS, teaming fertile alien jungles and forests with more swooping cameras that get EXPLODED, and just about anything else my crack team of 3d designers can project onto a green-screen... in 3D! (for no apparent reason).

What stars do you cast, if any?

Stars? Excellent! For a second I thought you might have said actors and then we would have had problems. Again, an incredibly easy solution: do a quick study to find out which impossibility beautiful young twenty-something (even if they are thirty-something) possible dolls all the kids are crazy about and cast them! Also, Lady Gaga will do the title track! Kids love her!

What do you save for the sequels?

More explosions? The next big advance in CGI? Supper 3D? The Empire Strikes Back and Return of the Jedi (so old! Must be remade... with Lady Gaga!)?

How do you avoid either the movie or the trilogy sucking completely?

I just outlined it. Use a title that has absolutely nothing to do with the film, but might have at some distant early point in time before the producers got their hands on the manuscript, EXPLOSIONS, use the most cutting edge special effects technology and advances in CGI (blow most of wad here) and 3d technology (the kids love 3d!), have plenty of action sequences and blood so the audience doesn't have time to think or get bored (audiences hate thinking or paying attention) which should pad out a 10 minute plot to a good 2 hours, and cast the most eye-achingly beautiful and popular people of the hour and you can do no wrong by Hollywood! And that is how you make a big budget block-buster movie that is garnateed to give investors a return on their investments (because most any time you have this much money sunk into a movie, profit is the bottom middle and top line!)

If you actually looking for a good movie, however, I'd suggest a much smaller budget to keep investors and greedy producers demanding hefty returns on their investment back. This will also constrain the excessive use of sets and pointless techno-gimmicks and force the director to hint and not show, eschew the action or horror gener (those lend themselves too easily to mindless action and blood padding which can go from excusable eye-candy to down-right horrindioius experiances at the lower budget teirs but, for some reason, dosn't stop lower budget directors from padding out a non-existant plot with them anyway). Instead focus on a humanist thriller (the Inquisition would be good for this, or, even better, just some poor manufactorum worker who the audience gets to see a few days of the life of), cast real but unknown and unrecognized actors, and don't try to cash in on all that Warhammer 40k is and everything in the setting, there-in lies disaster. In fact, eschew most all of it only focusing in one one small itsy-bitsy intimate piece of it (with hints of the wider universe to give the feeling that there's more outside, more beyond the drama of what is happening to this hab-worker and what he must do to survive for three days in this harsh enviroment). I would avoid, oddly enough, war, big conflicts, explosions, etc (seems at first blasphemous to the setting, but then, the setting is so much more beneath all that). They would be mentioned and spoken of by crusty old workers, family members, and preachers, but not shown or delt with in the story. The story would just be about that one guy and those around him and what they have to do just to survive in the lower-mid-hive, the horror of the low hive looming ever clossser by the day, a thankless job, a looming uncaring bureaucracy... somehting everyone can relate to ;-) If it's a good movie you want, then minimalism is the way to go -all other bloated rococo paths lead to not but shinny vapid baubles of recycled trash to pad a summer with and little more (just look at the clasics that have survived tiome, they almost always were made on the lower end of the budget spectrum with few investors and little in the way of any kind of hope of being in any way successful or income generating).

Graver said:


The screenplay is easy. In fact, it pretty much writes it self. Imperium bad, freedom good. A dashing 20 something hero, wait, scratch that. A beautiful 20 something strong woman heroine with a great rack who doesn't quite fit into the evil Imperium realizes how evil it is. Then there's some killing, she takes a shower, a cute 20 something guy on the wrong side is won over by her and together they make a really big explosion. Happy ending! The rest like diolog and all that can just be hammered out in a night or so or taped together from other screenplays.

Are you Michael Bay?

I would put the budget at $70 Million for the first film. If it makes a profit the sequels jump to $150 million each.

I like Paul Blackthorne for Eisenhorn with who ever the flavor of the week, 20ish-pretty-boy-with-washboard-abs-who-will-draw-women, for Ravenor. Ravenor doesn't have to do anything but look good then get crispy.

I don't think I could live with being attacked by masses of warhammer grognards on the internet telling me that it was heresy to let the screenwriter put a MkII Mars pattern adaptable thermic combustor reaction engine in a Leman Russ when everyone knows its only found in the Rhino and other varients. In the street there would probably also be finger pointing, possibly some finger poking action and I'd get punchy. lengua.gif

Christopher Lee as looming Lord Inquisitor
Michelle Rodriques as Sister of Battle
Kate Beckinsale as Moritat Assassin
Johnny Dep as Imperial Psyker

The adept, a junior aide to the extensive family household of an Imperial World's (Sinophia?) CORRUPT and DISLIKED Governor, uncovers a twisting plot veiled in the talk of daemons and aliens to secede from the EVIL Imperium. The Adept, moderate grade and from outstanding stock still toils at the grindstone. His struggle, the valiant fight to push this information to the hands of the overarching NEUTRAL and FEARED Imperial Authority, the Adeptus Arbites, is fraught with difficulty since their force was destroyed in the DAMNED CITIES debacle. We face an exploration of insanely astute businessmen, misanthropic socialites and gritty artists/entertainers, driven all the more by a mysterious outside influence supporting the Governor's seccession!

Michael Clark Duncan to play an adept, our central character. Typical character background, detail comes through in the supporting comics and the nuance of the acting, not the plotline itself, possibly also the award winning video game to go along with it. Like Wickus in District 9, he's got to be both likeable (i.e. you root for him as the viewer) but also generally distasteful too, showing us lots of 'off the cuff' moral quandry and things we don't quite approve of. (His goals, the things he admires include 'obedience' and 'ignorance', alot like Bilbo starting out in the Hobbit).

He's supported by a cast of Guardsman (who will routinely out-shine the adept at intellectual skills, but also be radical and vaguely loathesome, allowing an illustrative attempt to explain why this EVIL Imperium even exists in the first place), Noble-ish Techpriest (who has a bit of an Indiana Jones/Victorian adventuring flair to him) and a <someone else>

The key point is that the characters aren't allowed to be good because they're stupid or banal. Mistaken and wrong, sure, but like 'Star Trek' let's have it as also a bit of a poster for being 'actually competent' whilst also in the X-Men 3 style of making you suspect that the people who 'seem' to be the good-guys are actually alot less well-thought-out-principled than you'd first think.

In terms of action and drama, go for some sort of avant-garde film noir style. Remember the delightful Sin City? Something along those lines. Room for big explosions, awesome battles and such, but the strength of the film would be enhanced by 'minimising' these conventional 'oohs and ahs'.

The plotline? Straight conspiracy, almost a little like the recent Sherlock Holmes film. Not too convoluted, but paint it as a world where we know there are gods and daemons and aliens, but where crap stuff still happens.

Something along those lines?

Santiago said:

Christopher Lee as looming Lord Inquisitor
Michelle Rodriques as Sister of Battle
Kate Beckinsale as Moritat Assassin
Johnny Dep as Imperial Psyker

I'd replace Michelle Rodriguez with Milla Jovovich, personally.

Artemesia said:

I'd replace Michelle Rodriguez with Milla Jovovich, personally.

I like Milla Jovovich, but just about every film she's been in has been terrible... "Warning: this film contains Milla Jovovich."

Lightbringer said:

Artemesia said:

I'd replace Michelle Rodriguez with Milla Jovovich, personally.

I like Milla Jovovich, but just about every film she's been in has been terrible... "Warning: this film contains Milla Jovovich."

You mean, like 5th Element? sorpresa.gif

First Scene: Imperial Guard attacking a Heratic base on a frontier world. Start with artillery barrage? Laz fire everywhere, sentinals.
About 10 mins in tanks show up blow big holes in bunkers and vaporise people. Main characters, Inqisitor and acolytes (Gerard Butler, Kate Beckinsale, Orlando Bloom?) turn up (in valkyrie?) and break into a building start boltering and chainswording people, find evidence "It's already been moved."

Second scene: Inquisition HQ, toture some goons, adepts going through some evidence. Introduce Inquisitor Lord (Christopher Lee). OMG it's on a hive world.

Third Scene: Hive world starport or orbital station. Inquire find a bad guy, comence scene of inquisiting that makes Jack Bauer look like Dixon of Dock Green. Contact Inquisition and allude to back up.

Forth scene: Infiltrate huge heretic base on the edge of hive where they are keeping whatever doomsday device they are intending to use. Get discovered, main characters start kicking ass, Gerard butlers got a force sword and psychic blasting people. Heretics pull out some fanatics, huge beasts, pit fighter servitors, heavy weapons, kill one of the acolytes. Looks like they are going to kill our heroes...

60 mins exactly: Drop pods bust through the roof crushing a bunch of heretics, space marines pour out, commence twenty minutes of people being exploded, drednought powerfists some people and blasts alot more (plasma cannon). Terminators BAMF in and assault cannon / aload more. Most people are dead, inquisitors like cheers dude and space marine commanders all like, whatev's we be all made love for Emporer and sh!t.

fifth scene: Find doomsday device, big shock, it's a human or something like a little girl. Also it all blows up just as they are escaping.

sixth scene: They go back to I:HQ and the acolytes are all like, we saved the world and billions of citizens but Gerard Butlers Inquisition senses are tingling. They get back and Christopher Lee's like "I'll take care of this now K thnx by."

seventh scene: Gerald butlers finished having sex with Kate Beckinsale and she says something like 'it's not like Christopher Lee's going to turn that girl into a deamon host' and Gerald's like 'Sh!t, he's totally going to turn that girl into a Deamon host'.

Eighth scene: Confront Christopher Lee in some gothic dungeon who's all, 'bigger picture, for the Emperium, you fool...', Butlers all '**** move bro.' Christopher Lee's got a deamon weapon, slightly hit's one of the other acolytes (Orlando Bloom) who disintergrates slowly from the wound, like rot's away really quickly. He's also a psyker I guess. Butler off him, but Lee say 'Maybe you should have let finish binding that deamon host', Butlers like 'Crap'. Deamon host shapped hole in the wall.

Ninth scene: Deamonhost rampaging through the mid hive, people running screaming and being turned into deamons or piles of bones and flesh etc. Inquisitor hurls psyk out / vortex grenade in slow motion (so you can see that's it made of gold etched with a picture of the Emperor), boom, =I= kills beasty horray, everyone left cheers. Butlter spins round in slow motion coat spinning and strides off through cheering crowd before ordering a nearby stormtrooper to round everyone up for a good ol fashioned murdering. Fade to black

The End


Greenlight.

Almost perfect, worth atleast 2 Oscars, now if we somehow have Robert Pattinson killed by a flamer or Eviscirator or something we could ad another 2 or 3.

Santiago said:

Almost perfect, worth atleast 2 Oscars, now if we somehow have Robert Pattinson killed by a flamer or Eviscirator or something we could ad another 2 or 3.

Just having him in the movie would degrade the overall quality to below Oscar grade.

Again, depends...if we have him utterly destroyed, and show it in the trailer, we should be good.

As long as it is a trailer only clip and not actually in the movie, I think it might be OK.

Now as a DVD feature, that scene on an infinite loop could be grand!

Get Jerry Bruckheimer and Martin Scorsese in on this, and we may have something golden. Or a whole lot of arguing on the set. I'm not sure which.

-=Brother Praetus=-

I say, get Neill Blomkamp,´s and Tim Burton´s DNA, clone them into the new being with quickened grown and educate it with works of Herbert, Heinlein, Lovercraft, Matt Farrer and Aaron Dembski-Bowden.

Then, let it direct the Dark Heresy film.

Oh, and force Arnie to play Necron Pariah.

Defenitely Abnett. Though I would say the Ghaunt's Ghosts first. Then Eisenhorn. Then Ravenor. A lot of materiel for at least a trilogy from the Ghosts, which would educate an audience gradually as with the Guard, you don't have to explain the length and breadth of the 40K universe up front. Most people would understand the lot of the soldier, no matter the setting and context. Then, you'd have set yourself up for bringing the audience, and the movies, to the next level with Eisenhorn. Then the opus of Ravenor. After that, I dunno. I love the Space Marines, but they're too inhuman, too invulnerable, to really identify with. I think you'd get a much greater response to the Inquisition, and/or the Imperial Guard. They're people we can understand, and sympathize with.

Jhaeyde said:

Defenitely Abnett. Though I would say the Ghaunt's Ghosts first. Then Eisenhorn. Then Ravenor. A lot of materiel for at least a trilogy from the Ghosts, which would educate an audience gradually as with the Guard, you don't have to explain the length and breadth of the 40K universe up front. Most people would understand the lot of the soldier, no matter the setting and context. Then, you'd have set yourself up for bringing the audience, and the movies, to the next level with Eisenhorn. Then the opus of Ravenor. After that, I dunno. I love the Space Marines, but they're too inhuman, too invulnerable, to really identify with. I think you'd get a much greater response to the Inquisition, and/or the Imperial Guard. They're people we can understand, and sympathize with.

I'm not sure about starting with Gaunt's Ghosts - especially the first two books are really similar to the Sharpe's series, and we'd want to avoid turning newcomers off with cries of "ripoff." Starting with Necropolis would be good though - that's where it started to get really different and come into its own.

Personally, I think that Inquisition is a better entryway than Guards - Guards is mostly straight-up Sci-Fi military action, and it's less distinctively 40k than Inquisition. Starting with an Eisenhorn or Ravenor would establish the weirdness and wonder of the setting, which would give a following Guards story more resonance.

Vikingkingq said:

Starting with an Eisenhorn or Ravenor would establish the weirdness and wonder of the setting, which would give a following Guards story more resonance.

I disagree. Broadly speaking, while Abnett is one of Black Library's best authors in terms of telling a story (personally, I think Aaron Demski-Bowden is up there as well, and sometimes Gav Thorpe and Graham McNeill reach that level as well), I find that he completely misses about half the weirdness and wonder of the setting most of the time. Great story-telling, poor track record when it comes to depicting the universe, though he has been gradually improving since he started. However, so many people are exposed to Abnett's work first and foremost that many people think the Astronomicon shines out of his... sorry, nearly got into a rant there.

Honestly, part of it, I think, is a matter of origins - Dan Abnett was a writer first (having worked on comics and novels for years before he wrote the first Gaunt's Ghosts novel), while the ones who, IMO, manage to depict the horrific absurdity of the 40k universe more effectively all appear to have started out loving the 40k universe (and in the case of Gav Thorpe and Graham McNeill, were both games designers working on 40k before they started writing novels), generally meaning they're much more familiar with it.

I meant relatively to Gaunt's Ghosts. Of the two kinds of stories, which of the novel series has more? I would say the ones with daemonhosts, floaty chairs, tons of psykers, and triple doors rather than the one that's mostly human soldiers vs. human soldiers.

You guys are raising some of the points I always wondered about if you were going to have a 40k movie: what ORDER to put things in? Where do you start?

I agree with Vikingkingq, I personally don't think an Imperial Guard/Gaunt's Ghosts story is the way to go. I think it doesn't have enough of a distinctly 40k feel about it.

I would start with a Inquisition (Ravenor/Eisenhorn scale) initial movie, ramp it up to include a more violent, action orientated sequel featuring Marines, and end with vast planetary invasion in the final movie featuring Titans, Grey Knights and the like.

My other problem was always how to explain the complex 40k universe to novices...

I think the solution might be to have a principle, unworldy character who's a bit of a cipher who has to have the universe explained to him/her as they go along. The "yokel" character is always needed to explain complex setting points to novices. Luke Skywalker was this type of character. So was Doctor Stephen Maturin in the Aubrey/Maturin series. And Zael in the Ravenor series, but he was a bit underused in this role. These characters aren't necessarily stupid, but they don't know about the universe. By having the other characters explain things as you go along, you enlighten the audience without the clumsy device of a narrator.

Graver said:

If you actually looking for a good movie, however, I'd suggest a much smaller budget to keep investors and greedy producers demanding hefty returns on their investment back. This will also constrain the excessive use of sets and pointless techno-gimmicks and force the director to hint and not show, eschew the action or horror gener (those lend themselves too easily to mindless action and blood padding which can go from excusable eye-candy to down-right horrindioius experiances at the lower budget teirs but, for some reason, dosn't stop lower budget directors from padding out a non-existant plot with them anyway). Instead focus on a humanist thriller (the Inquisition would be good for this, or, even better, just some poor manufactorum worker who the audience gets to see a few days of the life of), cast real but unknown and unrecognized actors, and don't try to cash in on all that Warhammer 40k is and everything in the setting, there-in lies disaster. In fact, eschew most all of it only focusing in one one small itsy-bitsy intimate piece of it (with hints of the wider universe to give the feeling that there's more outside, more beyond the drama of what is happening to this hab-worker and what he must do to survive for three days in this harsh enviroment). I would avoid, oddly enough, war, big conflicts, explosions, etc (seems at first blasphemous to the setting, but then, the setting is so much more beneath all that). They would be mentioned and spoken of by crusty old workers, family members, and preachers, but not shown or delt with in the story. The story would just be about that one guy and those around him and what they have to do just to survive in the lower-mid-hive, the horror of the low hive looming ever clossser by the day, a thankless job, a looming uncaring bureaucracy... somehting everyone can relate to ;-) If it's a good movie you want, then minimalism is the way to go -all other bloated rococo paths lead to not but shinny vapid baubles of recycled trash to pad a summer with and little more (just look at the clasics that have survived tiome, they almost always were made on the lower end of the budget spectrum with few investors and little in the way of any kind of hope of being in any way successful or income generating).

Just as an aside, my favourite rumour about 40k films was the story that Steven Spielberg had asked about directing a 40k film... I just can't see that as being true, but the idea amuses me.

What would you feature in the screenplay? What's the plot?

A war film. The 40k setting is by and large the most violent, dark and downright nasty setting in sci fi out there, even if you have to dig a little beneath the surface to really understand it. My film would feature the Imperial Guard, Adeptus Sororitas and ultimately Astartes towards the end. The enemy would be the Archenemy itself: Chaos, with traitor guard, mutants, monsters and daemons galore. Throw in some enigmatic, but ultimately inhuman Eldar to the mix.

Plot outline:
At the height of a great crusade, Imperial forces are becoming bogged down retaking a system from the Archenemy, the film would revolve around the trials and tribulations of a group guardsmen as they slog their way through a warzone. It would chronicle their views and experiences of the Imperium's elite in the form of the Adpetus Astartes and Sororitas without requiring a focus on the characters of these two fighting forces.

How would you explain the incredibly complex Imperium to total novices using a practically infinite budget?

Using narration by the main character, likely a sergeant or lieutenant of a guard unit, combined with in-character chatter on the way to the warzone, the setting of the 41st millenium can be established. A brief intro scene showing Terra in all it's glory, narrated to explain a little history of the Emperor, Imperium e.t.c. Shots of massive troop fleets mobilizing, the power of orbital bombardments when they arrive, some space combat to boot. Massive battlefield vistas from aerial points of view. Finally into the film proper.

What action/set pieces would you employ?

Some things sum up 40k well - Astartes pods and the ensuing carnage they cause after deploying from them. Mechanicum Titans and the unbridled power they can unleash. Guard artillery batteries. Imperial ship designs and the incredibly monolithic proportions of space warfare. Sororitas acts of faith, including Martyrs. Chaos being utterly opposed to order, and thus the Imperium, demonstrating the vying roles of the 4 chaos gods through things like mass carnage, biological warfare, daemonic summoning, possesion, warp-tainted artifacts and Chaos Space marines.

What stars do you cast, if any?

For me, Tom Baker is an absolute must as the narrator. For any of you who haven't played Fire Warrior, go and watch the intro video on youtube, it rocks!

Jasen Statham would make a good Storm Trooper.

I have to mirror previous comments and say Kate Beckinsale, as we already know she looks amazing in a pvc catsuit, so would suit a Sororitas down to a T.

Ron Perlman as an Astartes (mainly just voice acting after all, as it'd be largely CGI)

Richard Dean Anderson as an aging Guard commander.

What do you save for the sequels?

Tyranids. Just when the Imperials think they have the system under control, a hive fleet rears it's ugly Norn queen head and attacks.

How do you avoid either the movie or the trilogy sucking completely?

By obtaining completely unfettered rights to make a 40k film without GW vetos or suggestions. Also don't post any material during production to get fan feedback - fans are horrible, ugly trolls with no ability to be critical without being nasty.

What would you feature in the screenplay? What's the plot?

I'm a big fan of focusing on an individual, or a small group caught up in their own, seemingly minor, affairs in a world/sector/segmentum/universe of larger concerns. I agree that it should be a war film, and focus on that however, I would prefer it if we are following a squad or, for DH at least, a group of acolytes dealing with some form of strike force or invasion.

Having the iconic entities in there is a must, maybe few but ultimately covering the remit of guard, marine, sororitas, civilian. Personally I would like to see a heretical bent, but not focus on Chaos too much.

How would you explain the incredibly complex Imperium to total novices using a practically infinite budget?

Using the "lets do this together" approach. It's a common trope to use a novice character, amongst more experienced, to provide exposition. Of course it has to be careful how this is done, but I can see it working well. Ultimately I wouldn't aim to cover everything, certainly hint at wider aspects, but focus on what effects the main cast and their personal exploits. Ultimately I think this will breed more familiarity than an overarching exposition.

Utilise the common tropes, so people can identify with the characters. The Marine out to proove himself against the odds can feel a whole lot familiar than the Marine fighting back the 'nid horse.

What action/set pieces would you employ?

As much as I would like large set pieces, back to the first question, I would want a closer shot on individuals. Certainly have the two legions battling it out, with titans and the like, but have that from the perspective of someone on the ground; or what the characters would see.

What stars do you cast, if any?

About the only person I can think of is David Lee Smith for an inquisitorial role. Not overly fussed otherwise.

What do you save for the sequels?

Different focus, or different perspective. Why not see and feel about the situation from the eyes of a cultist or heretic? Focus on one group at a time.

How do you avoid either the movie or the trilogy sucking completely?

I'll agree that GW with have to keep it's nose out of it. The people that should be working most closely on this are Black Library, the authors that until now have shaped the 40k setting into the Behemoth it has become.

It may be an idea, and may not go down well with fans of the book, but possibly a book adaptation would be good.