thank you for playing! I think you are the first one to actually complete the boss level (besides me who made it... not even my teammates finished it).
I am very proud of my level 12 three star solution that I've figured out, and for like three days I also had the record of 13 steps.
The mirrors were kind of a fail. If you check the main menu, you can see how my old mirrors looked like. I decided to change them before the last day and I didn't have much time to make them. I think they look nicer, but it also made it a lot more confusing.
Originally I wanted to make them a lot bigger to make them more clear, but sadly the front/back facing mirror's poles would have covered any arrows on the edges of the map.
glad you enjoyed the game and again congrats on being the first one to finish the boss level!