I think this is a neat game, especially that clicking moment of realising the levels were tiled. I did feel like the physics were a little janky, and as mentioned by others, I think having a preview of the mirror dimension would do you wonders. But some polish here and there and the game can be pretty good! Nicely done!

Let's start with bad stuff. Cat animation seem jittery to me. Mirror dimension flet like it had temporary graphics, and probably because of that sometimes things happened without me understanding why. Sometimes I died from what looked like fall damage but then I've fell for higher altitude and It didn't happened.  For the good stuff, main world feels nice and cohesive. I love the idea that you in small level but because it repeats itself it feels like a small world. Music doesn't grab my attention but it's subtle enough to make a nice background noise. From the whole game I've got the feeling of adventure and in some moments feeling of entrapment and wanting to get out

Very cool concept. Would be nice to have a way to preview the platforms that you are going to toggle into.

Interesting game idea, 

I would've liked some indication of the other "dimensions" as now I died quite a lot when switching dimensions because I was a tile off. Some kind of vague transparent effect would've helped immensely!

Made it to the end, very cool concept. I'd definitely play a full game with this idea.