For those who like puzzle games, in particular Sokoban, it should provide a good challenge of pace. For difficulty, at least 45 out of 50 puzzles could be considered at least medium difficulty, but most are actually hard. They can be solved, it just takes some patience and careful thinking.
The development has been quite low key, just because there is no real public relations involved.
There are some promo codes for the OSX store available, contact me for information if interested.
Version 1.1 is already in the works with a few minor tweaks and some localization (Japanese instructions).