I don't wanna contest your take just for the hell of it but this feels really incongruent with what I watched. Whether the movie is great or mid is less of a concern to me than the video game comment. The movie felt very traditional to me, translating a very loose 'creepy-pasta' idea into a traditional horror movie format.

To that extent I personally thought the movie did great, but I guess I'm highlighting my disagreement because I don't think there's any video game influence on this movie. I know there are a lot of games themed after the backrooms but the concept itself is agnostic to video games, it's a communal/shared universe like SCP that spawned from a particularly fire paragraph-horror story.

You might appreciate it a bit more if you see it as less of a 'video game' movie and imagined it more as one person's big-budgeted interpretation of a cultural horror idea. Sorry if I've read the wrong implication from your post and you already knew all this stuff.