Great game! I Beat it too!
Wonderful game, great graphics, sound etc. Loved the challenge.. the final moon was a pain in the ass (but I wound up beating it without losing a life)
Proof that I beat it:
cheatcodes were for: Invulnerability, Starting with Auto Particle Cannon, and Unlimited Ammo.
(I won't post the exact codes as that takes the fun away ; ;)