This is just a small demo of my upcoming game called "Sonic Bossfights". It has the same style of boss gameplay as Sonic advance 2.

Controls:

V to dash
B to spin
[Space] to jump

At the moment, the only boss is the second to last one where you gotta take on Robotnik himself, believeing to have destroyed ALL his machines. I won't spoil what happens when you defeat him, just ram him until he's beat. Robotnik alone has no defence, so running at the speed of sound OR spinning will do.