The sound when you go into the door is jarring, it clashes heavily with the peaceful music.
Sokoban puzzles aren't my thing, but this seems like a pretty good one. The tutorial is good, one short level to teach each concept. Simple, clean graphics. Pleasant music. I like the concept that he leaves a soul behind on every step, so you can't go where you've already been (unless you have the Kaxe). This is just from your page description, but it made me laugh that his doctor prescribed he goes to a dungeon.