It kind of felt like a puzzle game, trying to find the best combo of upgrades that didn't shoot you in the foot too bad. All the upgrades having a downside was pretty cool and was good for replay-ability. It is sort of just a survivor like style game, and aside from the upgrade system being a little different I maybe would've liked to see more in the way of tricks or more ways you could deceive the player.
But overall, simple and well executed. Good job.