Ok by sideloading using the Playdate website it runs. Must have been some error during download or copying then, sorry.
Thanks for trying these out! It’s still weird but I’m happy that it might have been just a coincidence (perhaps some problem with a case-(in)sensitive partition or just a borked copy). I hope that you’ll enjoy the game :)
To the potential future fellows who discover this thread while googling the same problem: let me know about it, please! :) If it happens more frequently, I’d like to know about it and fix it.