AliensInTheDark, an ld48 game.

Find the switches to open doors.  Go through the doors to go to the next level.  
Don't let the aliens touch you.  Use the healthpacks to stay alive.  The last
level is a dead end.

System requirements are fairly minimal.  You need a 3d card that can do 
copyTexSubImage2d() quickly.  It seems to work on a Geforce2mx.