Nah, the fake trees are getting better at blending into the forest.

This images has some tells that is was generated, it's possible some post clean up was done but when's the last time you've seen a mug with two handles? I'll admit those do exists, so it could be the artist's choice. On the painting on the book case, splitting the mouse's head in half is also certainly a choice....

Looking at the "game" it self, someone else mentioned the mouse doesn't fit in the tunnels. The gaps are inconsistent as well, some areas of the map are inaccessible, regardless of the characters Sir. The big cheeses are all different, and some of the cheese dots go over the green walls. Those aren't mistakes someone would make by hand, especially considering the amount of detail in the rest of the image. If it was a kid's doodle, I'd be a bit more forgiving.

AI is getting better, it's hard to tell what is and what isn't AI at a glance, especially when a human cleans up some of the obvious mistakes. These days you really have to scrutinize an image on the technical details/logic of it to decide.