Sonic the Hedgehog Thrash is a ROM hack of Sonic the Hedgehog 2 by DalekSam, though it was originally a hack of Sonic 1. It also uses the Sonic 2 Clone Driver.
You can also play as Knuckles, credit given to Spanner for the Knuckles object among other things. Honestly, I tried doing it myself but I failed, hard.
As of August 2013, the project has since been rebooted from scratch.
