Really cool concept! I made it up to Day 20 before giving up. I liked the visuals and your audio, but I do wish that the camera was a little more flexible (it was too close to everything), and it seemed like I could only place 3 structures at once to defend my key. After I hit game over, the game went unresponsive/crashed, but I enjoyed my first couple of runs at it before then. Thanks for making and sharing your game!