Nice Concept and idea, game is really enjoyable but i got some problem.
I got the problem when i started the Game, my monitor screen resolution is low, so when i launched the game UI items got hidden in right, all buttons like start, arena etc. i am not able to start the game. For this i am also a Godot game developer so, i highly recommend that you Use canavas_items in the Stretch mode in Project Settings, that will fix this problem.
After that i little bit struggled how to start the game but after it, game was too good.