It seems there is a known bug for devices running on Android 2.x. (Samsung Galaxy S1 and its siblings run on Android 2.x.)
From Retrica's FAQ #14,
I am using an Android device. Why can't I see the preview?
It often occurs if you are using devices that run Android OS 2.x version. Retrica team is aware of the issue and working on a fix. In the meantime, inquire your device manfacturer for any assistance to upgrade your Android OS to the latest version.
Probably, the only way is to unofficially update the Android OS version (to at least Android 4.0 ICS) by flashing custom ROM.