I have seen this game as "want-to-see-TAS'd" on some peoples' pages.
http://www.freewebs.com/suklaalevy/files/megadrive/DecapAttack(UE)(!)-WIP.rar
A rough run-through almost without power-ups. It takes 24 minutes but optimized could be somewhere near 22 minutes.
POWER UPS: (each lasts 10 seconds)
-Move faster and jump higher
-Extend your reach and strengthen you punch
-Let you control a powerful ball of light effective against bosses
Haven't tested this yet, but could be handy in slow bosses (Hovering Clam, Yeti and final demon boss). I don't know the real names as Gamefaqs gives so little information. Damn, I have to buy the "real" version :)
The rest are pretty much useless since there are no places where enemies make you wait for very long:
-Wipe out every enemy on sight
-Freeze enemy movement
-Make immune to enemy attacks
I see this as a potential publish-worthy game to do. How about you others?
PS. I have lost my skills to make hyperlinks :(