Some good games.

[sludgecrawler]

Goldeneye 2d
A small shoot-'em-up remake of one level in Goldeneye.
www.perfectrun.net/index.php?id=pageget/goldeneye2d

Crimsoness
A short visual novel with, maybe, interesting graphics.
www.rockpapershotgun.com/2009/01/02/crimsoness/

Black Shades
A bodyguard FPS with rag doll physics and simple graphics.
www.wolfire.com/black-shades

Cortex Command
Remote control bodies, protect your brain, kill the zombies and harvest gold, all with impressive physics and beautiful sprites.
www.datarealms.com/

Space Hulk
A fan-made computer remake of the boardgame original.
Unfortunately not available for download at the moment due to legal issues but you should watch the site now and then for updates.
Also, I think the first version might be available on other sites.
www.teardown.se/

Night of the Cephalopods
Experimental game with more and better voice acting than in most other games.
www.spookysquid.com/notc/

The Manipulator
A plattforming, shoot-and-manipulate-'em-up.
tigsource.com/articles/2008/12/31/the-manipulator

These are the ones on my usb I can think of that hopefully fits the criteria for this thread.

[wired22]

Played the manipulator and black shades before my PC got tore down. I was planning on playing cortex command but I have to get acquainted with my new OS. Black shades is hard (the best thing to do on the first level is go to the freaky red and white type thing) and the manipulator (though cool) I didn't have the patience for.