I was getting an email from one of the reader few days back regarding his iPhone problem which SpringBoard always crash while playing games. I would suggest you try SwapMode, an application from Cydia(jailbreak your iPhone if you wanna try this).
Basically SwapMode will allow you to switch between normal and game mode. Game Mode will turn off background services and SpringBoard Extensions such as SBSettings, iHome, etc. Your device will behaves as if it is freshly jailbroken with no app and extension installed, thus reducing the chances of system crash during game play. Normal Mode: Revert device to normal operation. Re-boot if necessary should it experience any abnormality.
Go to your iPhone Cydia and search for Swapmode and install.
File Name: .//deb/SwapMode1.1.deb
Size: 310560 bytes
You can use any kind of utility tools for measure your iPhone memory and you should see a significant change.
Hope this can help.
With Swapmode, you can enjoy your iPhone game without crash now!