Awesome job, it's really addicting! I like how rather than having the motivation for fighting be something usual like level-ups, etc, you made fights necessary to advance. The main thing I might change, if possible, is to keep the level music playing through resets. It's really minor, but I think it would help with the immersion a lot, as it was pretty jarring to hear it reset when I was starting to get into the flow of things near the latter half of each 60 seconds.