Hey Keitaro, please install latest version, this bug is fixed. Please Note that in order to update from versions 1.0-1.12 to 1.15+ you need to uninstall previous version( for future updates this wont be an issue), which on this case you will probably loose all saves made. Fortunately on 1.16 if you go in Options there's an option to Unlock All Levels, so you can continue playing from were you left. :-)