Fun game. Would be better if you had the option to send ALL of your ships with one command, and HALF of your ships (the sort-of standard for this type of game) with another (i.e. Shift+Click). The auto-transfer feature is a great addition to the genre. 4/5
For anyone having any trouble with this game, a laser, rocket launcher and machine gun on each level will destroy the creeps before they get half-way down the hall. Upgrade the guns as cash is available, spread out between the levels.
You literally don't need to swap elevators once the entire game after the first two or three training levels.