Literally unplayable due to lag and crashes

I love the Bloons series on PC and iOS, but this game is literally unplayable due to the lag. I am playing on a brand new iPad Air 2 with high computing and graphical power, and the screen constantly freezes as the frame rate drops to zero. The app will crash itself, losing progress in the middle of a stage, and causing items purchased in-game to be lost. Its really quite unfortunate since the game itself is great when it actually runs smoothly.

YikYaker about Bloons Monkey City