ITEMS!

[Alpha Six]

It can go one of 3 ways;

1) Make it heal damage.
2) Add a counter that tells you how many Rings you have. When you take damage, you spill all the rings you have, but you don't take damage percentage. When you take damage, they spill back onto the screen.
3) Same as above, but when they spill out, they fall through the stage if you don't recollect them while they're still in the air.

1 is simplest, 2 can have the potential to be slightly unbalanced, and 3 would probably look lame and I guarantee Sonic fans wouldn't approve. I kinda don't but it's a bit more balanced than 2. I dunno.