If you could, lower the RAM footprint of the game as there is devices that run at a slower frame rate after updating to ios6 and many apps have lowered there RAM footprint to allow for a smoother experience as there is lag when placing light-emitting blocks[glowstone...], running fancy graphics(was fine before ios6...). I really hope you do this as there is a large amount of people who own this game on iPod Touch 4G and the experience should be its best.