Hmm you shouldn't need to choose a file since each option (mac/pc) only contains one zip file... can you post a screenshot of the download pop up window that you're getting? No one else has reported this issue so far and I've tested that the download works on firefox, chrome, and edge, so it might be something to do with your browser on your end. Sorry you've been having issues with this, if I can't get the itch.io download to work I might be able to send you a github download link to play the game.
ugh i couldnt even get a screen shot had to take photo with phone email to self, and then upload as attachment here (yet to do fingers crossed) nope thats not gona work either because of size limit. really who has file size limits these days (okay at work im limited to 25 mb at a time but still really, 3 mb issssss toooooo smallllllll!) Anyways for what ever reason Itch and its browser wont let me dl the game to play it. Looks cool though, so maybe someday when you get far enough along to post a demo to Steam or something Ill get to give it a go.