Its very simple and fun. Really similar to games like diep.io, which are really fun. I liked the upgrade system, that was very neat.
Also the little icon the bottom left was nice to see if the base was getting attacked.
One thing, after I bought the the upgrade menu, I couldn't get out of it unless I ended fullscreen in the browser to press escape again, maybe make a button for that (If I didn't miss it)
However very good job! Would really appreciate it if you wanted to check out my game also :D