you have to pay to get past level 12 (to get most 2nd tier towers, not to mention keep levelling towers) great gameplay, but not enough to justify all the micropayments to unlock the actual content
quick tip for those looking for drones, I've been through areas 0-8 and the only drones I've come across are in 0, and it appears that market inventory is fixed soz.... fingers crossed for the final area being drone friendly
 "Heroes of The Banner"){kind=icon}
 "Astrox"){kind=icon}