Good fun! I used to play a lot of tower defense games haha. The machine guns shooting the birds were very satisfying.
For this one, even though the birds mostly come from one direction, the island was round and you can seemingly build everywhere so it was a bit hard to know where best to put your turrets at first. It may feel a bit inhibiting when during the battle phase you can't react to what happening for the most parts. If you had made it so that you get more money as the birds go down it may feel better to play and try to optimize.
The turrets are really fun looking!
Others have said it already but the audio got a bit repetitive haha. I gotta win this battle though!