I'll not add new features at this point, unless it can be done using the game's scripting features. Luckily, I have a few fun ideas that can be done with those that I may try out.
By the way,
Here's the developer editor for Knytt Underground. It's not at all intended for anyone but myself, so the interface isn't that nice. For example, in the room editor you have to press 1,2,3,4,5 to switch between editor modes, and after saving with Ctrl+S you need to press F12 for a program to repair World.bin file which the "binary array" extension breaks for some reason. Without repairing the file, the game may crash when loading World.bin - however, if no room exists in the top-left corner of the map, pressing probably F12 destroys the entire World.bin file so make sure to leave a room there.
Some copy/paste features in the editor doesn't work right at all. So again, while the game is very nice and solid on the inside, the editor is in fact not. It has been hacked together to work with any new feature I've added to the game. That's why I really want to make a user friendly editor for the public (but it's unfortunately a lot of work).
I'd happily provide the MMF2 source for the editor if anyone wants it.
Anyway, my point is this: If you create some cool areas that matches the quality of the rest of the game, it'd be my honor to add it as a part of this update. Just don't make it too big (in that case, it may not fit into the current map). This is a chance to get your own level content into the main game!