Its perfect! Just, not.
This game has amazing physics, that play true to the game! I'm like... wow! Then I play it a few times, and there are bugs... a few bugs.
Like, I would randomly fall through the ground. It was very annoying. The rest are just nit-picking.
Your character should flash invincible after getting hit. Spikes would kill me because I landed on them twice. Frustrating.
When "reving up" (Down+Space) you can get attacked, and technically it's in ball form, you should be able to destroy enemies in that form.
Tails can attack the first boss as by flying into him. Not sure if this was intedned... but it made it very easier. On that note.. nice bosses. They were challanging, but not frustrating.
Make it longer! It was good the first two-three times, then it got repetitive.
But then again, it's Sonic, so I can't give it anything lower than a 9. Make another, please.