Notes on Ultimate Mode:
1. Get just about every life you can find. Even if you're good, CEZ3's boss is good at cheap hits because of his shielding spikeballs.
2. Get the chaos emeralds. Not for super sonic, but for those ring bonuses which lead to lives. Also, if you have all 7 emeralds and get a token, it seems to give you a ring/free hit (not sure).
3. Choose your best character. Super sonic is not gonna happen, so don't pick Sonic for him. There's no dishonor in picking Tails if you go the best with him. In ultimate, I use Knux, mainly for his gliding, which can get you.... more lives.
4. Invincibility powerups are still around. Use them.
There's more, but I'm too lazy to go on.