OP, I found your capx to have a lot of small problems. There are a lot of good suggestions in the thread here that you should do.
C2 doesn't support more than 8/9 collision points. Squares only need 4.
Family up your events(ie no blue on touch, blue on red.. that's bad, bad bad bad bad. )
Your Evertick eats too much.
I've come to testing design for my personal computer. Create a test app. run the test app on your minimal target device. once you get the performance you want by adding features. note down the CPU usage on your computer for the exact same app.
As an example using my PC and iPodTouch4g.
My PC will have a CPU usage of 3% to maintain 55+fps. Any more than that will exponentially drop performance.
So your EveryTick often hits my computer with 5.8% here and there. While often fluctuating between 2.8 to 4%. So when it hits 5.8% it starts to cascade the performance.