The last year and a half I have been living together and working with a small indie team on the game Forced.

We are in the middle of our Kickstarter campaign, and it would be so awesome if you would check it out:

http://www.kickstarter.com/projects/betadwarf/forced

It is similar to Left 4 Dead in the action co-op aspects, it has some puzzles similar to Trine and is similar to Diablo in terms of themes and aesthetics.

If you didn't notice, Adam here on RPS played some of our game:
http://www.rockpapershotgun.com/2012/11/12/impressions-forced-demo/

It’s a tactical co-op action game for 1-4 players. We also have something we think is pretty innovative and interesting, the Orb, a player shared character.
(More about that in this video: http://www.youtube.com/watch?v=6PbsSmjjJYg)

Cheers!