we need to be able to set our towers to target clumps of units, or stronger/weaker units, instead of just having our towers hit the first thing that comes their way
a way to see the total damage the tower has dealt, to see if its working or not, would be really handy, along with a speed button and a few changes to the strength of certain towers. i think that instead of unlocking certain upgrades for towers as you go, it should be something to spend skillpoints on, just to deepen the strategy
a good game, but i think there should be a shop of some sort, where you can buy accessories for your duck with coins collected in training, and also, when you complete the game, there should be a sort of freeplay mode, where you can get unlimited levels for your duck, and see how ridiculously fast it goes