it happens how racoon has said, instead of assembling anything, it just goes to the character. it happened in my first play, and coming back to a save, and even resetting the browser didn't fix it on my end. i use google chrome, and when i get home in a few hours, if you haven't been able to reproduce it, i'll happily send over a video of it :D
i know bugs like this happen, otherwise from what i've played the game is really good. its got a cosy vibe and is really simple in a good way.
I pushed an attempted fix about 10 - 15 mins ago. If you reload the browser / download the new version it should be fixed. Or is this problem still happening? If it's still happening you can send us a video of it, that would be super helpful. either to our email: lasse@unsigneddouble.com or you can send it to us on discord.