Core Mechanic: The controls and towers were all simple and self-explanatory. Although the upgrade system broke a bit; I was trying to upgrade all of my towers a few times, but all of my upgrade points seem to have gone into a single tower at the back of the map, giving me a tower with infinite range (it seems like the upgrade button specifically applies to the most recent version of a tower that was placed)
Game Feel: It's always satisfying to hear the tower noises stack up over time until I have a big collection of towers making cool noises, and this game is no exception. Ditto for watching the towers snap into their spots with a nice click sound.
Visuals: The objects are all visually distinct, and the colors are pleasant to look at.
Sound: The music was fun, and the shot noises are meaty and distinct.
Theme: The feedback loop of building towers to get more resources to build more towers is a ramp-up from a small input of resources (especially if you manage to crank points into an infinite-range tower)