Pop-ups are blocked and i play in browser (firefox)
Maybe it's just me not being used to this website but i don't see where i can download the game?... i only see a play in browser option.
So, the reason it's likely erroring for you is that pop ups are blocked. The program I use has the achievements come up as pop-ups, so when your browser blocks them, it will also be blocking some of the code from playing out, which then results in an error.
I've seen itch.io marking downloads so I figure there has to be some way to, but I'm not quite sure how if there is... I'm very new to uploading here, I'm sorry to say.
If unblocking pop-ups doesn't fix it, the only thing I can think of is either trying it on Dashingdon or Moody.ink, as firefox should run it fine otherwise.