Simple and fun! I like how you paced the levels introducing one element at a time. They get a little frustrating in the yellow zone, when you introduce the double screen levels. The problem is they are presented along with the mines, wich break the flow of the game and make those sections feel extra long and repetitive. I feel they would be used better in those fast spike-dodging sections where levels last only a couple of seconds anyway. Having to wait for the mines to explode, and then dying on another mine you didn't see because it was just behind the door feels cheap. Overall, It's a really great game. Keep it up!