Basically, there's a Zero(from megaman X4) at either end of the screen. The one on the left is player one, the one on the right is player two. An orb is in the middle, it will go to one of the players. Your objective it to bounce it back by attacking it. Every time you hit it, the damage of the orb increases by 5. The health of the player is located just above they're head. If a player misses the orb, then the orb damage is deducted from the players health.