I've been recently been thinking about Arkane Studio's Prey which is a immersive sim, with a pretty good rogue like dlc, that probably has one of the strongest hooks of any game I've played. If you liked Halflife, System Shock, or Deus Ex it's definitely worth a play.
Are there any titles that might not have been commercially successful that you feel everyone should give a shot?
I picked it up on sale after watching Fury Road, which in turn I put off watching for years because I really like the first trilogy and did not want to have that memory tainted by some cash grab Hollywood sequel. Boy was I wrong about the film, and I was equally blown away by the game, to a point I felt really guilty getting it for 10 bucks or so. I really, really wish there was a multiplayer, though.
I almost gave up in the beginning because I had never played a game that relied so much on hand to hand combat. I'm so glad I pushed through.