There are a few great free games, so post a few here!
Doukutsu (Cave Story):
http://www.miraigamer.net/cavestory/
Really, this game is just awesome. A masterpiece of game design.
An 8-bit side-scroller shooter, strategy, RPG etc… etc…
Yume Nikki
http://www.indiegames.com/blog/2008/04/fre…yume_nikki.html
Play as a young girl and enter her disturbed and strange dreams.
No story, no real point but to collect all the masks in each dream world.
I’ll post more as I find them, if you know of any; post them here as well.