Thank you very much for your feedback!
Unfortunately we had to make do with using a bunch of asset packs, but the plan is to draw them all so they're consistent in art style ^^ We'll keep the sound mixing in mind and fix that soon.
And yeah, I'm not sure what causes the error myself (nothing google will tell me, but I have a feeling it has to do with all the variable checks the game does that web builds struggle with) , but if you would like a less annoying experience, please do download the non-web builds as they run fine!