Textual words of the creator:
"Concerning gog and web versions, have in mind that Steam version is in a "early access" mode, and this means that changes and experiments are being done. This is not reflected in gog because gog and web versions are supposed to be solid/finished versions, where the player won't find unfinished things, like the multiplayer. In fact most of patches are for the level editor and multiplayer stuff.
As soon as new features are included, tested and agreed by the community, they will be updated in gog and web. Most of the last changes has been done in the unfinished multiplayer that are not available in other shops.
Nowadays, for instace, zoom option, automatic invoentory sort option and English dubbing are being done. As soon as these options are done, they will be updated in web and gog."