You know what the Sonic the Hedgehog series has been missing? Dangerous levels of obesity resulting in adult onset diabetes and eventually death, a glaring omission corrected in the Sega Genesis hack Sonic 2 XL. It makes Sonic a fat-ass.
The trick here is to avoid the onion rings scattered about Emerald Hill Zone and Chemical Plant Zone. They replace the series' traditional gold rings and turn Sonic the Hedgehog from pot-bellied speedster to portly spiked hero to, ultimately, wheezing, sweating, immobile mound of flesh and fur. Yes, rings are bad for your health and Sonic's waistline.
Responsible for Sonic 2 XL are "Ranger" and "Captain Bozo" of the Sonic Retro forums. Their ROM hack is available for the gorging on at the link below.
But first, a gameplay video.
And second, a Sonic 2 XL gameplay video set to "Hearts on Fire" by John Cafferty from the Rock IV soundtrack. I mean, why not?