I've noticed a lag with mmf iOS games every now and again but could never quite put my finger on it. Some people have reported this as a delay or lag on the touch controls of upto half a second.
I've now got an iPad to test with and I'm spotting a repeatable pattern to this lag. In a simple game with a few active objects, background objects, multiple touch and accelerometer objects and the platform movement object, with not many events and with no common gotchas like fast loops or large images/memory use, I see the lag every time I restart my game after powered up. If I press the home button to close the game and then restart it, the lag disappears and runs at normal speed.
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In the above you tube video I wake up the iPad and start the game. The fps is around 40 and the touch joystick is slow and sluggish. Tap the home button and then restart the game and now the fps is around 60, the animation is noticeably smoother and the touch joystick is smooth and responsive. The game will play fine from this point onwards. However if I put the iPad to sleep and wake up again, the game is slow on first run once again.
No other (non MMF) game appears to have this problem. I've seen this happen on the itouch too although not in a repeatable way. I have a bigger almost complete game that will sometimes exhibit this lag on my itouch, not yet tested on the iPad. I can't say I've noticed this on cave diver or just survive. Not sure what conditions my two games have in common that shows up this lag...maybe the color reduction setting? Maybe having multiple touch and accelerometer objects in the frame? Not sure what else the two games have in common?
I can post this game over to you Andos, Francois if it will help (pm where to email it).