This dude is just, so goofy to play as, I love how the jump physics and instant acceleration emulate the movement from the TGF games, the killing dead thing is a nice touch but the lack of a recovery option means bosses can be a pain to deal with even if you don't get hit by attacks, since you may die from simply hitting them instead. Either way, he's a fun character in his own way, and you've done a good job at recreating that 1998 gameplay.
Excellent recreation of SRB1's gameplay. His janky gameplay makes him really interesting and challenging to play. Though, doing a full game run will turn each stage to "How many lives can you get" to prepare for the boss fight. Though I personally find that fun, so it's not much of a negative in my book. Only suggestion I can make is to make his rings collectable, as hard as they can be able to get. This would make boss fights a lot easier.
This is a pretty neat recreation of SRB1 Sonic, I like it! Though, it'd be nice if you could also bring back Super Sonic as he was playable in SRB1 Xmas, and had Earless sprites. If so I think his color should be on the sprite instead of as a super color [to match how his colors were animated in the original], as well as transforming with Jump instead of Spin, with no animation or music.