Just finished reading the section on Insanity and Corruption. I felt a bit disappointed tbh; it feels a bit lazy and is unclear. I understand that Marines are different and thus more desensitised to these things and so they have to be handled differently, but it's a little confusing to follow where they explain that and then provide the systems for use with non-astartes characters (who are likelty only NPC's anyway). However some of the rules I don't understand: how on earth does the battle trauma 'ear of the emperor' work? It seems to suggest that it happens at the start of th emission, not triggered as a truama. There is no errata entry for it.
There is also no explanation of how battle trauma's end and the rules seem to suggest that healing insanity points (a very vague process, almost as much as the guidance for awarding them, which is unfortuantely none) doesn't actually heal the associated problems. So a Marine that gets enough insanity to trigger a battle trauma will always suffer that trauama until he dies, the same with his primarch's curse - once he reahes the thresholds where that, at increasingly severe levels, manifests healing insanity points will have no effect on that. Is that intentional?
Also the Ultramarines seem to get off easy; their first primarch curse level is completely ineffectual since the players (and thus the ultramarine squad leader) will have zero input in what mission they are going to play since the GM wrote it and it's either that or nothing! How many GM's write up a variety of adventures (ie missions) and give the players the choice?
I also think they missed a trick with Corruption. It feels like they phoned this section in, I'm afraid. Perhaps this crosses over too much with what Black Crusde offers, but I think including a 'minigame' where marines can become corrupt, eventually being excluded from the Emperor's light, but without necessarily turning into horned goats or tentacle wielding monstrosities could be an interesting part of the game. By making it either you are either not corrupt (less than 100 points) or you are corrupt and thus unplayable misses a trick, but perhaps this is the subject of a later sourcebook/Black Crusade. After all there are 40k novels where the protagonists are chaos space marines. Such characters wouldn't even have to be avowed servants or slaves of chaos or members of the traitor legions, they could be akin to ronin. Certainly in the 40k unvierse they would be branded the same as any chaos space marine, but in the game there could be a chance for redemption perhaps while the character seeks to atone or at least stave off the enslavement of the ruinous powers?