I loved the concept, great theme interpretation, it requires some brain rewiring at first, and then it's 200% fun
I especially enjoyed the fact that there is an active part to it, as shooting manually with the main character, this allows the player to do some savings for the first waves, to set up a bigger plan
The balancing is really hard in this kind of game, and you managed to do it well, it was not too easy, not too hard (I'd say still a bit hard probably, but it's fine once you get used to the core mechanics)
Obviously, we quickly figure a "meta" like small turrets are really cost-efficient because they help in early waves and also act as walls
The polarizer is a really interesting turret, but I only used it (with walls) in the last level/last wave to alter the pathing+give a use to projectiles shot by the other side, otherwise it was complicated to find it a use
Random suggestion you might have thought of already (if you intend to update) was that:
Neutral basic attack was just an extra input to me, since it's slower I'd just press <tab> twice to get the right one, so I would have removed it probably (I figured out after that I could have put two polarizers close to each other, and rotate around them, spamming some neutral shot)
I think my favorite one after the last one (which allowed me to try every turret) was "Broken compass" (2) (I had to make the pathing really complex)
So great game for such amount of time (it looks well-designed in terms of code, you even implemented network), without any politeness I would definitely play more!
Good job @liqMix on art, and @Amaruuk (?) on the 3D art also :)