I'm probably not the best one to be giving the review since its late (At the time of writing this), but from the little bit I've played, I've really enjoyed them so far. I especially like the gameplay changes made to Espio, giving him more of a focus on horizontal momentum rather than 'Everywhere' momentum.
I don't like how Espio looks in-game however, at least compared to his older iteration. His limbs especially just don't look right, mainly when he's walking and running.
Nonetheless, I do like how each character plays. Not only does it fit perfectly with how they played in Knuckles Chaotix (I wouldn't know, I only played Classic Espio, Vector and Charmy from Sonic Classic Heroes) with new twists to make them more unique and fit in the new 3D environment, Heavy and Bomb especially.
Speaking of, Heavy and Bomb are quite uninteresting to look at, but the mod creators *did* try their best giving them cool poses, mainly with Bomb.
Vector's Beat Bounce takes a while to get used too, and Mighty's Wall Kick too but that's mainly because its used by holding space (Mind you, pressing space mid-jump causes the Ground Pound) instead of Spin like I assumed it would be. Definitely a "me" issue though.
Personally, my main issue is the custom title screen. It's cute and extremely well-made, but I'm one of those weirdos who activates a bunch of mod characters to have a huge roster and the Chaotix-specific title just doesn't sit well with me??? Maybe there could be an alternative version without the title screen.
I know I'm being really negative, but in all honesty, the pros vastly outweigh the cons in this modpack. Most of the issues here are either personal issues, easy fixes, or just me being hasty to write a review and not fully getting used to some abilities. (Heavy in particular is gonna take a lot of getting used too, I can tell.)