You are Jack, a Doctor/Inventer who must shrink himself to the size of a microbe, enter his wife's body and destroy the virus inside of her. 14 levels or so of brain twisting mayhem. Has a neat story. If you define neat as weird.
This was Seth's entry in a Ludumdare 48 hour competition. This updated version is a bit easier and has a new sound effect.
Works on fairly wimpy computers. (It's 2d))
Download link: InnerBody Install (1.5 MB)
Full source code is available on www.codedojo.com.