What browser are you using?
I noticed that Incognito tab in Chrome doesn't work properly on itch by some reason
Regular Chrome works for me, but try Edge too, it's interesting to see if it works.
Also, I'll be really grateful if you send me console logs from your Chrome. That may help me debug. To do it, in Chrome right click and press Inspect, then choose Console tab on the right. Go from the first level in the game to blank screen and copypaste whatever messages are in the console tab to https://pastebin.com/