The description of the game alludes to cooperative gameplay, but GOG doesn't declare cooperative among the game features (nor states this feature as missing in the game description, as it usually does in these cases).

So, to keep it short, does this game have coop on GOG? If it does, is it via LAN or Internet?

You cooperate with your past self :)

It's got a time rewind mechanic, so this would be somewhat impractical with a real coop over LAN or otherwise (unless real time travel gets invented :P).

I don't have this game btw, but a kind of similar one (Project Temporality).

Ok for the time rewind mechanics, but the game was alluding to cooperating with the cat simultaneously, and I quote "Control both the girl and the cat simultaneously".

However this game definetly does not have coop in the common sense.

Thanks