I now have ReQognise working perfectly on Playbook (without having to modify its cross-platform Qt code!).
In fact, I now have all my applications working on Playbook thanks to the successful port of Qt to the Playbook platform (thanks octorian).
ReQognise for Playbook Beta available here (no longer representative of the game).
Known bug: Holding down touch to pick up objects doesn’t work, just swipe it across quickly.
Sky is the limit for the Playbook. If you have any favourite opensource Qt applications you want me to port to the platform, just leave a comment here.
ReQognise (and my other apps) will appear on Playbook’s AppWorld when the NDK (and Qt) becomes official.