Update Dec. 15th, 2017
System
We changed the method saving the game progress. Now your progress data will be stored in *.sav files instead of old *.dat files. If you launch the game after the update, the game will automatically read the data from the old files and create a new ones.
However, the data will be reset on devices where the "line 41" error has already occurred. Therefore, please make sure you start the game on a device where the game is yet playable. Once the data conversion is complete, the "line 41" error on the other device will also be resolved.