While Stick Game the fight is primarily designed as a party fighting game it could also theoretically be a fun competitive game, but this has a big caviate, alot of the mechanics aren't well balanced and so have to be controlled, ish.

These are the safest bets for weapons in Stick game the fight for balancing, a strike through means it's bad and umbalanced and a question mark means it's of questionable power, if it's left alone it's fine.
Snakes are banned completely because well, they're one of the most frustrating mechanics in the game and all of the explosions should be picked with caution.

I'd suggest only using Forest or Ice levels, due to their platformy level design and lack of major gimicks, medieval levels and factory levels could be used but pick these with caution.

These are just some basic ideas for a competitive balanced gamemode.
Additional insights include.
No health regen.
100 HP.
That's about it really, feel free to suggest stuff in the comments bellow,