Could you allow players to access it on the web (play it on the website) rather than requiring them to download it? Thank you!
I have a few more suggestions if it's possible in the future:
Add more voicelines (when the game begins, when the game loses)
Add more monsters the longer the player goes
Add more elements and a way to combine them if possible
You start with the main elements, but you can buy more elements the more points you have in the shop
Add rounds, after a round, that's where a player can stop and buy elements
Add a boss after every 5 or 10 rounds
Maybe customize the way your bottles look for aesthetic?
After defeating the boss, allow the players to move around the world, where each monster is an element found in that area.
Maybe make a character of the voice speaking, it could be a scientist helping you from an element monster mutants that are ravaging the world (or something)
These are just suggestions, don't mind me.