Craving for some hints or improvements ideas 
It was really fun. My screen went off due to inactivity, maybe you can consider some tricks to preventing it to loose focus. Aside from that, very well done!
First of all welcome to the forum cybulskimateusz, that is a super solid first post. The game is actually really fun, it has that chaotic party energy already.
Since you asked for crazy ideas I am going to go slightly unhinged here. What if the arena slowly starts breaking the laws of physics the longer a match goes on. Like gravity randomly rotates 90 degrees for everyone at once. Or the floor just peels away in chunks and floats around as moving platforms. You could even have a mode where every player has a tiny black hole attached to them that gently pulls nearby objects and players in, so fights become this weird orbital dance of chaos.
Also imagine if spectators could mess with the match in real time. People watching could vote to spawn something absurd like a giant rubber duck obstacle or make everyone’s character twice as big for ten seconds. It would turn normal rounds into complete nonsense in the best way.
On the more practical side about the screen going off, you could maybe add subtle periodic input like a tiny camera sway or background animation tied to user activity, or even a gentle keep alive ping that ties into a visible effect so it feels intentional. Or just add an optional setting that plays a very faint looping ambient interaction that keeps the device from thinking nothing is happening.
Overall though this is already super impressive. Tighten the chaos, lean into the weird, and you might accidentally invent the next unhinged browser esport.