I really liked this! I like that you have a thematic reason for fighting these waves of enemies, and the arena is fun to walk around and explore. If I had anything to critique, it would probably be the fact that every time it says YOU DIED, I would be like, Yeah duh, that's why I'm here XD
Also I really liked the skeleton collapse animations. Doing the animations was something I really enjoyed in my own game, so it's fun to see cool animations in other games!