The performance is still severely degrading on iPhone 4 after 33 or so levels. 33% of the CPU being used on a static scene with just music playing doesn't seem too great either.
Allocations seems to worsen the problem, it uses a lot more memory in allocations rather than out. And the performance is worse, too bad to test.
So I've been using the system monitor tool to determine memory usage, and the game peaks at 80 in the difficulty selector. There are no performance issues in the difficulty selector, but at 75 there are ingame (it slowly works it's way up every scene change). But then when I go back to the menu, the 75MB usage stays but the menu runs at full 60 fps. When I go back into the arcade, the game runs at 60 fps until the same set of intensive levels where it breaks. The absolute breaking point is the fading background, which was trivial before these problems started happening
This all broke with either iOS5 or the first "scene switch time is accounted for in frame skipping" attempt where fps under ten was limited to 10. Are there any remnants of this in builds afterwards that might be making frame skipping go funny?
(haven't tested on non retina recently)
EDIT: I tried b52 but it didn't compile, something about not being able to delete the folder under games-ios?
EDIT 2: If I pop most of the balloons and leave the game without doing anything the fps recovers, which wouldn't happen if it were a memory problem. Nearly all of the leaks are gone anyway so that wouldn't make much sense.