The ClassiCube version for Android currently requires Android 2.3 at a minimum, as multiple system libraries that ClassiCube depends on were only added in Android 2.3
(Although it might be possible to rewrite the code to avoid depending on those system libraries (so that ClassiCube would work on Android 2.2), it would still take quite a lot of code and research to do that, so is unfortunately unlikely to be worked on any time soon)