No it's not a copy
quite a big coincidence!
I had an idea to make an japanese school horror game from 3 years now,but was never dedicated to making it
Then ,I actually came up with this idea and started working on my game around 6 months ago. I was inspired to make it an annomoly game after playing exit 8
The original name I chose was just The Corridor, and later I added 13 because I thought it sounded catchy and fit the horror theme with a playable 13 ingame level experience for players—kind of inspired by the name of Friday the 13th.and even make it not sound generic.
I honestly had no idea there was another game with such a similar name and genre until you mentioned it, and definitely this game is not even close to or a rip off your game.all assured ,thank you so much to mention.and i am more than happy to see if I can help in any way if it is conflicting your project in any such way!!!