Add Life
While playing game hit pause and press right, up, b, a, down, up, b, down, up, b.
Change shape (Fireant, and Shield bug.)
Start a game and hit pause then press c, a, l, l, d, a, d until you hear an orb weapon. It isn't done yet so don't un-pause. Keep entering the same code until the sound stops. Un-pause and you will be a fireant. Pause and proceed with c, a, l, l, d, a, d you will be a shield bug. When the shield wears off you will be invincible.
Different Weapons
While playing the game hit pause and press c, a, left, left, down, a, down.
Health refill
While playing the game hit pause and press b, a, b, a, left, up.
Level Select
While playing the game hit pause and press up, right, a, b, a, down, left, a, down.