You are the green planets, your AI enemy are the red planets. Each planet generates fleet resources over time (based on its size), which you can send to other planets. If you send more fleet resources than a defending planet has, it falls under your control and begins producing fleet resources for you instead. Take over all the planets to win the game!
This is the first game I made with Unity to learn the editor. I experimented with a bunch of tools from the Asset Store, but ultimately ended up only using vanilla Unity, ex2D, and some free art assets. Mouse and touch input are both supported (tested on Android). It's buggy and unpolished, but I learned a lot about Unity, which was my intent for this project.