great!
great game, little story would be great.
helping guide
the first... 15 levels you can do solo, no turrets needed, for the first two levels dont spend any money, your turret can take em out with one shot, at level three upgrade your damage, you can take two more levels then, then upgrade damage, and you can take the next... 4 or 6 levels or so.. you get my drift, level up your range as you see fit.. around level 16 you will need some turrets if you cannot keep up on your 1shot kills, turrets can lower them down just enough so you can get by with out losing any survivors
*note this is on easy mode*