Pretty good!
It feels kind of frustrating to constantly backslide as your ships are destroyed, but it makes the game more involved than your typical clicker so I feel it's a fair tradeoff. I did end up having to use an autoclicker to make progress in a timely manner though.
The human rockets were kind of difficult to tell apart from all the visual clutter as I was trying to click them and protect my ships. It might have been nice if they were a different color from the alien rockets or something.