The Last One

You are the last man left on the universe. You decide to defend your base on Mars clinging to your life with the towers you are able to build. But is it worth it? Is it worth it to go on?

The Last One is a tower defense game where you upgrade the monsters that are trying to attack you instead of your own towers to gain more resources to build your towers.  

This game is made by 3 game design students in a week for Space Game Jam #2. We'd appreciate constructive feedback.