Holy smokes this is good.
I only made it to the second level, and I had collected the key, but I couldn't find the mirror again before the enemies whittled me down. But I'm definitely gonna finish this one once I've tried some more of the entries. (And that I looked up how to save.)
The upgrading and skill process was so smooth and intuitive. It's impressive how much depth you created in the time frame.
And terrific use of the theme. I didn't pick up on the opposition because my stats were balanced, but playing as two characters that have mirrored stats is such a cool idea.
My only niggle is the cool-down on the turning, which is a bit narrow. I got spun around pretty easy. XD
But still 5s across the board.