This game had promise, but later levels become a function of tedium with constant need to adjust turrets. I enjoy the premise and I enjoy Tower Defense style games, but I don't find micromanaging turrets any fun. If they add in a tactical pause option I may find myself going back to those levels and changing my review accordingly. If you happen to enjoy that sort of gameplay mechanic you will probably enjoy the games later levels, but if not I really couldn't recommend the game. There is also the problem of gamebreaking bugs, see below for details here. That is the short summary of why I can't recommend the game personally. For further details keep reading.
+Great premise which freshens the stale Tower Defense genre.
+Voice acting is generally humerous.
+Variety of turrets/upgrades is relatively small, but generally each feel unique.
-Micromanaging turrets, which may be a plus for some people but not for me. Also, here a tactical pause would alleviate this con.
-Gamebreaking bugs, after my 6 or so hours playing the game the game froze and or exited to windows a dozen times. This usually happened when a new unit was introduced and then it would freeze/exit and I would then have to start all over on that level.
-Turrets/Upgrades while unique feeling would benefit from more upgrades or options. Also, the idea that all the later turrets take up more space on the ship and thus generally undoing what benefits the stronger turret gave.
That is the overview of the game, in my opinion. I will update my review, if/when they update patch fixes for the tactical pause and gamebreaking bugs.