Knuckles' Chaotix has a few quirks when compared to other Sonic games. The first and most obvious is that the player controls two characters instead of one. This makes gameplay quite different, but a tutorial at the beginning of the game helps explain this adequately.
A cutscene preceding the boss fight at Speed Slider.
The next most important change is that there are no live meters. When at 0 rings, and a partner is hit, he grows big and flies off screen. In a few minutes, he will return, but this leaves the player exposed. When the partner is hit, he loses 1 ring, while the player loses all rings when hit. If a large number of rings are lost, a giant ring will come out and if the player collects it, he will regain all rings. If not, the ring explodes into smaller rings. Normally in a sonic game, only 20 rings come out and the rest disappear forever, so this makes the game unique.
Also, unlike most 2D Sonic games, this has short cutscenes that precede boss fights. These usually explain the circumstances of the fight.
