Doom is a great homage to the classic FPS genre, and respects its roots by letting you kick demon ass, brutally.

A great early access game where you make weird, cool and sometimes complex contraptions to wreak total havoc on castles and soldiers.

Thief: The Dark Project (Gold) is a really great stealth game. It's definitely a game that redefined the stealth genre.

Instead of Running and Gunning, this game is all about teamwork, and survival.

Great game with rogue like fun, in a dark atmosphere with fast paced, dark humoured 2D gameplay.

A great space sim with creative strategy involved. This game also has a great modding scene as well.

Another classic by Valve. Great Co-Op with friends. This game Is great vanilla or with community made mods which spice up the experience.

Brutal Co-Op zombie shooter, With great brutalities, weapons, and even slow motion kills.

Great multiplayer to play with friends, Even better with the amount of community made content.

Brutal Hack n' Slash with A Top-Down View, With brutal shooter/brawler gameplay.