I think there is a little bug after Checkered room. When I went to the path (right) after a room, I somehow returned from the same path back to the room. I tried many times, but still I didn't get through. Eventually I watched my combass during the way and I noticed that it turned without any reason. I also noted that my screen flashed.
Has somebody seen this bug before? I got through after a few try.
This is how I did it:
SpoilerShow
I went first forth and back before I go on the way (or something like that) and I got through.