I really didn't understand what do to at first. Including a tutorial in-game would make it much better.
But when I got it... dang, it just doesn't let the player rest! I couldn't even get soldiers to the spot because enemies spawn constantly! Some kind of pause when exiting a soldier and opening the shop would be nice.
The idea of separating soldiers didn't really work since only one can be controlled at once. Try different controls!

Bugs: trying to merge with no soldiers stops the soldier forever; sometimes only having one soldier or one cube destroyed ends the game.
 

It's really not bad, I'd love to play it if it wasn't that difficult!

First thing I must say is. Woo, you relly got it close to the deadline. I don't know how much time did you spent with making it, but I must say you did a good job. If I may suggest some improvement, you really should add some kind of camera contol when you contol soldier(Rotating and zoom). And the hurt soundeffect will be in my nightmares. But otherwise you did a nice game.

Good job