Hi there! Thanks for checking the game out!
Unfortunately, as far as I can tell there doesn't appear to be a good way to link iOS or Android purchases to itch.io purchases, nor to host mobile files on itch.io... I'm very sorry, but it looks like they would have to be bought separately.
About your problem: have you tried exiting the game from fullscreen mode? On windows it should be either 'command-F' or 'alt-enter' to switch I believe. Though this is far from a perfect solution, so I'll definitely be working on doing more fixes to resolution for the next update.
And also, you can forfeit your character and get back to the main menu by using the "Quit" Button in the additional information tab. Just press around where your health bars are and you'll get more options. Hmm, that could probably also be made more clear in-game...
Thanks again!