Best defense game on NG
beats all other contenders into the ground.
Great simple idea very well executed.
The difficulty (dispite some peoples complaints) i feel is very good and balanced.
I re-itterate someones earlier comments on hotkeys... would be useful for glue and tacks.
Took me a while to complete on hard, few changes of tactics etc. but once i was there it wasn't too bad.
***SPOILER***
My hard game tactic was starting with boomerang's with multishot (sonic boom is a waste of cash) get about 3-4 of them then get 2-3 bomb towers (upgraded shot, dont bother with distance) then make as many boomerangs as possible with the multi shot.
For the last 10 levels (40+) have atleast 7 tacks down on each side of the exits (i used about 30 tacks for the right exit on the last level ((only had 1 left after level)).
So in short, this is possible on 2 towers, the key is quantity, placement and tacks... lots of them.
(Ps - dont overkill on tacks either, they cost twice as much as they make).
(PPS - Never found this 'cheat')
*** END OF SPOILERS***
Great sequel to towers 1, personally i think these are better than the bloons games.
Awaiting towers 3 with glee.
If i could make a humble suggestion, try adding a level customisation option on 3, ie set amount of cash, levels, balloons etc.
KUDOS!