There was a glitch or something that wouldn't let me change the difficulty from Easy to anything harder or even Casual, which was easier. If someone can tell me why this happens I'll make a note of it for future players, but it was frustrating to not play at the level I wanted to.
I think the game is still good, however, and if you like classic Sonic games you'll like this one.

StEJ2's Challenge Mode is a game mode that insists upon its difficulty, while still maintaining the hallmark jankiness of the franchise, which usually ends up trivialising boss fights. They still end up being the only engaging parts of the experience, especially in the late-game where stages just have long stretches of precision platforming segments with few checkpoints in between. If you're able to wall-jump while using keyboard controls, I'd recommend foregoing playing with a Gamepad just to make your life easier.

i hope lake feperd sees this and is proud knowing that i tortured myself for a ♥♥♥♥♥♥♥ year trying to get the F.M city platinum time medal.

3D Sonic-like platformer.
(+) Really nails the speed aspect!
(+) Good soundtrack!
(+) Has a "parry" mechanic that's really satisfying to use in bosses
(+) tons of content, as usual for the series from what I can understand
(-) controls can be quite finnicky
(-) most of the stages were not very good

buy this AFTER playing and 100% spark 1 and 3. and wait for a sale. this game is kinda rough

Do you yearn for the Dreamcast and Gamecube days of Sega? The halcyon 3D platformer era where you can go fast and explore? This is a Sonic game in wolf's clothing. It's an incredibly technical action game where going as far and fast as possible is the point. It has a bit of cheesy story beats, lackluster combat and parry mechanics to deal with bosses quickly, but this game exemplifies the query of 'can I get over there'? From the very first level's skyscrapers you are tested to see where you can reach entirely optionally. Admittedly, the score system rewarding you for collecting things in succession makes about as much sense as Nights or Billy Hatcher. The lack of a letter ranking system outside of Gold and Diamond medals is a real shame, but doesn't take away from the exhilarating gameplay and amazing soundtrack. Also has some cool speedrun tech if you're into that sort of thing. 4 stars.