Fruit & box artwork, original introductory puzzles and game: Guoguo Sokoban.

The 36 classic challenge layouts are © David W. Skinner, selected from:
Microban (2000), Mas Microban (2002) and Sasquatch (1999).
Original set and puzzle number are preserved in challenge-data.mjs and shown in the game.

Author's distribution terms: These sets may be freely distributed provided they remain properly credited.
Source and permission: https://www.onlinespiele-sammlung.de/sokoban/sokobangames/skinner/
Original level files:
https://www.onlinespiele-sammlung.de/sokoban/sokobangames/skinner/m1.txt
https://www.onlinespiele-sammlung.de/sokoban/sokobangames/skinner/m2.txt
https://www.onlinespiele-sammlung.de/sokoban/sokobangames/skinner/s1.txt

Only exterior non-playable spaces have been filled with walls for rectangular rendering.
Playable geometry, box positions and targets are unchanged.
The Microban selection excludes the author's identified third-party-derived end levels.