I found the idea quite fun. The controls are a bit clunky and slightly uncomfortable. I think if instead of J and K, it were the left and right mouse buttons, it could be more intuitive. I missed having a pause menu where I could restart the level. At one point of desperation, I ended up jumping off the main platform and had to reload the page to try again. I loved the upgrade mini-game; it seems like someone has been spending time defending Super Earth in their spare time lol.