We are investigating background drawing issue on iOS 5.
Update: Version 1.3 has been sent to Apple to address this issue. It will be available on the App Store in 1-5 days. Thanks for your understanding and sorry for any inconvenience.
Update 2: New version is now available.
Update 3: Updates of old versions (original, Advance, Bravo, including HD versions) has been sent to Apple.
Update 4: Updates of old versions are available.