eyy, this is a nice demo. Enjoying my time with it. Also love the music. I do think the level end jingle needs another pass though, it feels just a bit discordant.
I know "Comparison to another thing" is a thing that annoys a lot of artists, I don't know how it'd go with someone making a fan game, but I mean this as a huge compliment: It has the vibe of if the team behind Jazz Jackrabbit made a sonic game.