It's a faithful port of the Space Hulk boardgame. Not the Warhammer 40,000 tabletop strategy game - just plain ol' Space Hulk.
If you're not familiar with Space Hulk... It was a spin-off from Warhammer 40,000. It featured Space Marine Terminators making their way through cramped corridors and fighting Tyranid Genestealers. Heavily turn-based. Very slow-paced. Not a whole lot in the line of character development or depth. Think of it kind of like a 40k version of chess
The videogame does a good job of porting that to the computer, while updating the visuals to match what we've become accustomed to with recent Warhammer 40,000 releases.
It's still a slow-paced game. Still heavily turn-based. There's not much you customization or character development. There isn't a whole lot of storyline. You've got Terminators plodding through cramped corridors and killing Genestealers - just like the boardgame.
If you've enjoyed the boardgame and you're looking for something you can play solo, you'll probably be pretty happy with Space Hulk.
If you've been enjoying the other Warhammer 40,000 offerings on Steam and you're looking for your next hit, you'll probably be disappointed with Space Hulk.