In a single sitting, I made my way all the way to the final boss. And then I remembered why I couldn't beat it. If you die while fighting the final boss, you are sent three levels back. And these are the hardest three levels of the game. And its not even getting sent back from using a continue - if you die once while fighting the last boss - even with 50 lives - you are sent back. It's infuriating.
Everyone's been saying that I can't beat this game, and I'm starting to believe them. That last boss is unreal.