I played a lot of games (like 24 games) before I realised there was even an exp mechanic, after that it went quite smoothly!
It also wasn’t clear that the aim was to kill the center monster.
I spent a lot of the beginning of the game confused as to what the portal was, and why there were 221e numbers around it.
So I think the biggest issues with the game are the lack of clarity on what is required and what to do. After that it was fun. :)
Well done for making it!