The last two worlds bring this game down significantly. Managed to get through them only once I committed to creating save points during levels as well, as there were so many scenarios stacked on top of each other (poor hitboxes, whatever's going on whenever you try to jump while on staircases, superfluous maze-puzzles etc.), that I found myself getting more and more frustrated. It didn't feel like I was getting better, only that I was beating my head against trial-and-error annoyances. Granted, this could also be just me who suck ass at 2D Mario, and that more experienced players gets through this blindfolded, but it did feel less than fair towards the end there. Still, when you move through each obstacle and find that flow, it's a different breed of satisfying. Looking forward to see how the 2D-sequels will fare in comparison.