Really nice puzzle game. The "immune to undo" mechanic is good and the puzzles stay manageable from the size of the play area (unlike traditional sokoban games, that get big and include many boxes).
I started playing version 1.1 and now see that version 1.3 exists. Starting version 1.3, I can switch between the earlier puzzles and the latest one (the game correctly remembered how far I got), but I cannot actually play any puzzle. Clicking on the picture, or the level number or hitting ENTER or SPACE will not do anything.
Is this the expected behaviour (after all, this was a 'cold upgrade') or is there some way to continue with version 1.3 without the need to redo all the earlier puzzles?