A text-based adventure in Inform, regarding, apparently, some manner of missing penguin and the search therefor.
Pngwn is playable, and - of a sort - completable - but not truly finished.
You might want to play it before delving through the source code. The .z5 file is the compiled game, to be played in Frotz. Look for pngwnxby.z5 (e.g. pngwn2b5.z5) as the beta release for playing. Straight pngwn.z5 is the alpha release with debugging.
Compiles in Inform 6. From memory, alpha releases are compiled with -X and maybe -D, and beta releases with -S (which inform might add by default). Beta releases should be compiled with their version in the name, so version 2.5 becomes pngwn2b5.z5
Beta releases need two adjustments in the source file, commented at the top. New releases also need a change in the welcome messages, towards the bottom of the file.
Release minor version wants updating in the alpha after each beta release, ready for the new beta minor release.