Interesting things in your game
Umm.... I guess there is only one mechanic. Is it fun? Kind of, but yeah only for 30 seconds or so :P

Comments or issues you had?
Due to having a busy weekend, I treated this as a bit of a speed run. My aim was to get a fully functional game in as short a time as possible (that wasn't terrible). I hope I succeeded there... I initially aimed to spend 2 hours on it and I streamed the result with a timer in the bottom corner. This was fun! I wasn't going to submit but in the end I spent another half an hour to add a tiny bit of polish and this is the result.

Given the mechanic and AI are pretty simple, the main problems I had were silly things like trying to get the missiles to launch in the direction the gun was facing. The gun was rotating around the earth, and could be aimed on its own pivot. In the end I was using transform.forward to find the initial direction of the missile, but due to Unity's weird 2D I should have been using transform.up.