I quite like the game, I'm a sucker for a solid rhythm game. And the hentai is a nice bonus too! Like another commenter I also have similar problems with the gallery and can't back out once I enter a card, even when I try the fix that was suggested. Therefore id say this game is definitely worth bookmarking for the moment that those issues are fixed. Although honestly if you just want the rhythm part then definitely pick it up! Good game overall.
Thanks so much for the comment!! I have uploaded a bug fix which hopefully fixes the issue of being stuck in the image viewer.
I think it maybe is cos some phone screens may be more sensitive to finger movement and will consider some taps as tiny swipes instead.
So I tried to adjust the sensitivity of the "tap" that is required to exit the image viewer, and also made the Android "back" button that is part of the operating system also exit.
With both these things in place hopefully people can quit the image viewer now, I'm so sorry for everyone affected by this. Please grab the new .apks to see if it works.