So many it was discouraging, to be honest. For starters, the gym area went to a black screen when I tried to load up tutorials and forced a hard reset, even though I could hear my character walking around in the background. The next reset, I decided to wing it and went forward, and it crashed during the wave combat section. The next reset, it didn't register my WASD keys. The reset after that, I managed to get all the way to the end (though an enemy flew up to the top of the level and wouldn't come back down during the wave section, only for him to vanish and the arena to skip wave two entirely and jump straight to three), and when I went into the portal at the end of the level nothing happened. My character vanished, but the game didn't change screens or start loading anything else, and I could no longer open the menu or use any controls.
The game is just entirely broken, really. It barely works at all.