Proper

Doom II is the second game in the series, and it uses the same engine as the original. It introduced new monsters, a new weapon, and 32 new levels. It is also playable in GZDoom, and most of the information of Doom applies here too.

DOOM needs no introduction. It is the grandfather of the FPS genre as we know it. The GZDoom engine is a port of the originally DOS-based game that allows for high-res OpenGL graphics, mouselook, some widescreen support, among other things. GZDoom - http://grafzahl.drdteam.org/

Hexen: Beyond Heretic is a fantasy themed game, based on the play-style and premise of Doom.

Heretic is a fantasy themed game, based on the play-style and premise of Doom.

Final Doom is a spinoff of Doom 2. It has the same weapons and monsters as Doom 2, but it has 64 fiendishly difficult levels. It is playable in GZDoom, and has the same flaw that Doom 2 does (not pictured)

Oblivion is the fourth installment of the Elder Scrolls series. It is a 3D Fantasy RPG in which you choose your own path through the land of Cyrodiil.

Marvel: Ultimate Alliance is an 3D Action/RPG that is essentially the spiritual successor of the X-Men: Legends series. You can chose from over 20 playable heroes and interact with over 140 other characters from the Marvel Universe.

Bloodrayne is a third person action game from Terminal Reality and Majesco. You play as a secret agent vampire named Bloodrayne, and must shoot, slash, impale, and occasionally suck the blood out of Nazis. Aiding you are several supernatural abilities such as superhuman strength and agility, enhanced vision, heat vision, and bullet time.

NASCAR Racing 2003 Season is a racing sim from Papyrus and Sierra (and should not be confused with the much inferior but similar sounding NASCAR Thunder 2003), and the final NASCAR sim from Papyrus (EA Sports now owns the rights). It includes all of the 2003 tracks, many of the drivers, and an engine realistic enough that actual NASCAR drivers have been known to use this for practice.

Defcon: Everybody Dies is the World's First Genocide'em up game from Introversion Software (The last of the bedroom programmers), developers of Uplink: Hacker Elite. In Defcon you play the role of a military Commander hidden deep within an underground bunker. Your mission is to successfully exterminate your enemy's civilian population whilst disabling their ability to attack your own. The game supports multiplayer for upto 6 players, multiplayer in demo version is restricted for 2 demo players only. Defconwas released on 29.September 2006.