The challenges are a lovely idea, but... wow... it is sooo buggy...
I tried it (just for fun) on multiple smartphones (1 pretty new Apple, 2 old Samsung and 1 very old Asus) and Steam Deck (Linux and Windows). The browsers I tried are Opera, Opera GX, Safari, Chrome and Edge. With each combination I had different problems: stuttering, general slowdown, not recognised clicks/taps, graphic glitches, missing text and so on...
This is not to be meant offensive! Just information! I think most people will immediately stop playing after the first try...
This makes my fellow dev heart bleeding... I recognized, it's alpha state, but maybe you are a bit to early for testing in the wild...
Good luck fixing!