Hi! After messing about with the itch.io page's settings and reading online, it appears I cannot create a browser-game that also allows you to download it... I thought it was possible as I've seen in the game's analytics that some players have "downloaded" the game, but apparently that metric is about in-app user plays...

That said, you can get rid of the itch overlay by pressing the tiny "full-screen" icon at the bottom right (see my screenshot below). Hopefully that makes the game more playable for you!