I wish Nitrome would address the Level Select bug that appeared after the latest update. Progress is not saved when returning to the Level Select screen; you'd basically have to play the levels in one sitting to progress, starting at Level 1. Sent them a bug report email but haven't heard back yet. We'll see.
As much as I admire Nitrome, I kinda hate that they are always working on the next thing and leave past games to rot (with the exception of Leap Day since it's their baby)