Cool math game, I didn’t expect it to be a rail shooter and definitely didn’t expect the end! You got the difficulty curve just about right. ;-) Some of my suggestions:
-
It took me some time to figure out how to type answers, so I had to restart the game. Maybe you could add a brief text explanation in the menu.
-
I think you need to add a crosshair in the center of the screen, because it can be difficult to eyeball the calculator guys.
-
A speedup key would also be nice, because sometimes you clear a room and still have to wait for a long time to leave it.
Overall (A), great game! Very nice art style (A+), fun and fitting music (B+), challenging equations (A+)! :-P