I know gamepads work great, but I think it would be better if the keyboard/mouse controls were up to that standard, too, as it would improve the accessibility factor.
BTW, I noticed two strange things when trying to play with keyboard/mouse...
- The game could only handle two inputs at a time. This made it harder for me to get a handle on the controls.
- I found a glitch where, after a certain point, the arrow key inputs would become inverted. I'm not sure what caused it, but when it happened, the game became unplayable for me and I had to stop.
Overall, though, I'd say it looks to be a very promising rethinking of Sonic's controls. It just needs a little bit of touching up, that's all.