From what I was on YouTube, it does seem to be multiplayer because there are 2 YouTubers names 8-bit Ryan and Dawko who seem to be playing together. Thats the only evidence I am aware of honestly. The game came out a few days ago on steam and it was made the original creators of Little Nightmares 1 and 2. Little nightmares 3 with probably the one you are referring to as it is not even cross platform or couch friendly and both users have to own a copy of the game. (which btw, best place to buy it is on steam to avoid needing to get ps plus/xbox gamepass)