Thanks for reporting these, I'm glad you had a good time playing it regardless! ^^
For 1. I have an idea what causes it. It's sadly a result of how the engine acts when skipping through moving sprites, but if it happens you can press "Back" until the character appears on screen, then move on as usual. I'll try taking care of this when I update the Android version, and I can make the menu buttons larger as well.
Have a fine day too, and feel free to tell me any more issues you run into! :>