When playing this card does the oppenent lose the cards to there discard pile? Or do they remain in the oppenents hand and you just get the effects for free?

Since "Slaanesh's Domination" aks you to "play" the card, it should go to its owner discard pile (like any "played" tactic card).

What if you don't for some reason want to play those Tactics revealed? Back to hand of the owner?

When I read some cards, like Slanesh's Domination, it looks like FFG tried to save some ink when publishing the game, why didn't they try to explain card effects better?

shiba_nivengo said:

They needed to save ink so they could print three pages of ads in the back of the rulebook, which no one can argue is a better use of rulebook space than say, rules.

Dam said:

Technically they are still in the opponents hand when they are reveled. The only reason for them to leave is if they are beeing played.

What more does the card need to say? Reveal them, play them for free if you can/choose. The card doesn't say you should or can discard any cards not played, and normally you cannot so without an additional effect spelled out there is no reason to think that they would go to the discard pile in this game. Anytime a tactic is played it goes to the discard pile unless there is some card effect that say otherwise, so there is no reason to think they could keep them after they were played in this game.

Regarding more rules less adds... frustrating for sure.