here's a little tip: if you want to take over an enemy tower use fire ball just before your troops reach it (it will almost always return to 0 population), this way it's automatically yours ;)
yay beated the game.... this is how to do it dont buy those tentacles just buy the dart upgrades and some missle upgrades (up to 2 heat seekers) then save up for the last dart upgrades and then youre ready for the tentacles