Jumping for Joy
Great puzzles! I knew from the original game that a sequel was in order. Nothing new except new levels in this game from the original "Jumping Box," but it's still great.
These levels are definitely harder than the original. But folks will enjoy the game even if they haven't played the original.
I wouldn't recommend a third level pack, though, unless there are more hazards, larger levels, etc. Have you given thought to making the box go on a side-scrolling-type adventure?