Something odd: I had a couple hundred million dollars, went to log in under my congregate account and when I came back just seconds later I had over 8,000,000,000,000. I had just started investing in shrimp boats. By the way, I'm not complaining. :)
(SPOILERS!!!!)
The last level went just fine until my tower AI targeted the minions, rather than the boss. Why would my gunners go for skeletons that were running into a wall of paladins rather than the enemy right in front of them - you know, the enemy that can't afford to lose his head?
I noticed something strange and repeatable: On the Trox level I used two archers to take out the three air units in the first wave and that worked fine. The next time I played the level with the exact same placement and found that the archers failed to win EVERY time I added a swordsman at the choke point leading to the base. So the choice was either to fail to kill the air units and be ready for the ground forces or kill the air units but then rush (and fail) to build ground units in time to intercept the next wave. Does attack speed decrease (maybe by splitting the AI between units?) as more units are added?
 "AdVenture Capitalist"){kind=icon}
 "Epic Creature Hunter I"){kind=icon}
 "Kingdom Rush"){kind=icon}
 "Demonrift TD"){kind=icon}