My project is has the same problem... creating all the pixel grahics has taken a while, especially when one feels compelled to go back and redraw things again and again. I also underestimated how much time doing the maps would take (detailed 150x150 tile maps, plus dozens of environment objects, plus collisions, it can't take that long... ....right?) Ten worlds is not gonna happen, unless I make tiny maps, but pulling a stunt like that is out of the question.
On the plus side, I feel all the work has leveled up my pixel arting a little.