Enter the following button presses during gameplay, but not while the game is paused.
Flamethrower: Press Down, Right, Down, Right, p.
Four-Way Weapon: Press Down, Down, Up, p.
Three-Way Weapon: Press Right, Right, l, u.
Two-Way Weapon: Press Up, g, Up, g.
Pulse Wave: Press Up, p, Down, Right, l.
Shield: Press Down, Left, l, p.
Speed Up: Press Left, Left, Right, Right, g.