I tried to make a game in one day, and wound up stumbling onto a mechanic I think is pretty darn sweet. A new enemy spawns each time you make it successfully to the ship, and all previous martians spawn in the exact same place as last time. After several martians have spawned, it becomes very difficult to navigate successfully to the ship and the payer is forced to memorize and perfect a route that actually works.

My mind was especially blown the later levels (20+) where you are forced to experiment and travel super intricate paths to freedom.

I love this game, understanding that it is not the most developed. I hope you do too but you don't have to.

P.S. Thank you adamatomic for flixel!