I've designed a number of levels now and things are going well. There should be a great deal of variety from level to level, more so than in the first game, and most of the difficult-to-program 'objects' I've added seem to be behaving themselves. Little alterations to the code here and there as I go along helps keep everything else honest (pigs were literally flying during the last level!).
Just being able to set the size and shape of the level multiplies the possibilities many-fold. So for example I can have a vertically scrolling, block pushing puzzle fest followed by a forced horizontally scrolling saw and spike dodging level, with a free roaming enemy chuck-fest after that. Ideas are coming thick and fast and I hope I can do the game justice.
There should be some stuff in the game that even seasoned platform veterans haven't seen before.