I marshalled some players and got through a session zero and simple investigative scene using Imperium Maledictum and have been recently reading back through my old Dark Heresy and the new Imperium Maledictum adventure anthologies to get a sense of the structure of these things - not that I couldn't just do "5-room-dungeon-but-40k" but I wanted to try and get a sense of how 40kRPG games ought to be run officially.
The big difference is they seem to follow a three act structure; each of those then broken down into two bits. There is a thing to find out so go to a place and resolve the problem there to get the clue to lead onwards. Essentially solving minor mysteries to get clues to the meta-conspiracy behind it all. The first and third acts are the set up and resolution respectively and the second act is an accordion you can expand or shrink as much as the mood takes you. Essentially, the 'gather clues' second act can require finding as many clues as you see fit.
The big thing for Dark Heresy or Imperial Maledictum is the players are primarily investigators - even when levelled up and quite punchy, they are not the heavy firepower of the Adeptus Astartes. The thing they can do which the various big guns of the setting cannot is investigation and social pieces. You are not going to sneak your way through a masquerade ball with a Warlord Titan but then that is not its job. Combat in Imperium Maledictum is also pretty vicious with critical hit tables that will see you dead-dead on the first shot if you are unlucky. This is combined with the 'superiority' mechanics of granting chunky bonuses in combat if you have gained intelligence on the adversaries or the battle-site to make pre-confrontation gathering of information highly desirable.
The broad recipe seems to be
- pick three locations, connect them all by a thread
- have two things to do at each location, maybe have an extra clue that might be found
- have a further location where the big bad or revelation is
- front it all with a briefing scene
