A hack based on Sonic the hedgehog 2 made by snkenjoi

Aperture Science's Portal Gun finds its way into Sonic 2.
The portals in the game actually affect objects other than sonic - to the extent that you can kill an enemy with its own projectile if you fling it back at it.

Credits:

E-122-Psi - sonic's spritesheet
flamewing - help with collision detection
iojnekns - portal sprites
FraGag - testing