Really clever game! Already the one-way walking and the direction changing was clever (actually kind of similar in a way to our game :P), but adding the colored blocks that changed whenever you changed screen really elevated this game. I think there are a lot of super cool puzzles you could make with only those elements already. Really well done! I enjoyed this one a lot :D
By the way, the game is indeed a bit finnicky about window size. I avoided the full screen as you suggested, but even just zooming in on my browser webpage broke some things. It didnt spoil the game at all, but I just wanted to let you know :)