Open both the upper left and upper right warp doors. Enter either door, and keep your character in the door that he transports to. Most of the discs thrown at your character will pass through without harm. Keep your character at this location and break the enemy discs that appear. Throw your disc to keep only one opponent on the screen at all times.
Move and shoot simultaneously
Use controller one to shoot discs while using the D-pad on controller two to move or vice versa.