Metal Slug Advance: Final Boss HELP

I need help beating the final boss. I've been trying for three weeks now. All I can get is it to catch flames. I don't have any cards to use, since I usally die at least once before the end of each level. Someone help me out with some tactics. I'm about to shelve this game for good.

I had the same problem as you, but I figured out beating him was just a matter of patience. You -can- beat him going in with no cards/upgrades. Just keep aiming for the eye thing and make sure you -always- grab the heavy machine gun ammo when the robot drops it. You'll get the most bang for your buck if you stand directly under it when it drops down to the lowest level and unload a full clip of heavy machine gun ammo into it before it can fire off too many of the blue lasers. Memorize the patterns and after about 5 or so repetitions of the patterns, the machine will be done for.