This was a lot of fun! It feels as polished as I've come to expect from the "Penguin series".
You have to keep an eye on a lot of stuff, and the reloads add some danger and mean you can't recklessly fire missed shots all the time.
The difficulty ramp works nicely - it doesn't feel unfair, but you quickly get overwhelmed if you're not staying on top of those tanky ground troops. The best score I managed was 8,300.