This is a great interpretation of the 'not real' theme. There were a lot of little subtle touches here that I really liked such as being able to change your door selection at the last second after clicking one - this made you not only have to watch out for the small mimic movements, but gave you the option of making a quick decision and hoping the doors would validate it with an animation before your character got there. The mimic eating sound effect was also very satisfying when you died.
I think this might have benefitted from having levels rather than just being an endless loop, but I appreciate you may mot have had time. Would make a really great mini game in a high fantasy RPG!
Really good work there! :)