I love the game until the very last stage (or maybe second to last....it looks like the last area anyway) which just seems to have a massive difficulty spike. Can't get past it.

Everything people are saying about this game is 100% spot on. It's like Dark Souls mixed with Megaman and Ducktales. Incredible.

My roommate and I had problems with the boss endurance fight near the end because we were using the conjurer's coat (purple armor), which weakens your defense stat significantly.  Using the dynamo armor instead immediately made it beatable.  You really don't need magic as much as you think when you get the bonus mid-range attack from down strikes that armor gives you.