Alright, I've got a few things to say, both some positive stuff and negative
Firstly, the positives. I love the squash and stretch animation he has, it adds a bit more character to him. His move set is also pretty solid, I like how his drop dash animation makes the Jumpball glow a bit more, and i like how you can drop dash after doing a thok or homing thok bouncing off an enemy.
As for the negatives... he feels... a bit too slow?
I tried running through GFZ1 as Normal Sonic and then as Neo, and I was able to get 27 seconds as Normal Sonic, but i got 35 seconds as Neo, of course, 35 seconds is still pretty fast, but it feels weird to have a modded sonic that's slower than Basegame Sonic that doesn't have any extra gimmicks (like Snolf, who is very much a gimmick character). Also, I get why his dropdash overrides the shield abilities, but I think it could've been nice if you made it so you could still use the shield abilities with custom1 or something (similar to what Adventure Sonic does, letting you use some shield abilities with one of the custom buttons)
So basically: it's pretty good, but could use some improvement