There are ways to speed fluidly through each level, but they do require practice and memorization. The levels are also designed for slower exploration, if you prefer a more cautious pace. A lot of players will start off moving slowly through the level, and then gradually learn the fast paths. Then, much of the…
You missed a step. The Japanese game Doki Doki Panic became Super Mario Bros 2 in the US, which then went back to Japan as Super Mario USA.