It’s a known fact that some entertainment, when being translated from one country to another, tend to change a few things. Heck, the same thing applies for anime, which tried to rationalize the culture appearing on screen into an American subtext or just change it completely (unlike now, where the material is kept mostly the same as the original).
But Super Mario Bros. 3 for the NES is an excellent example of the little things and how Nintendo slightly modified the game, in both big and small ways, when they released it in the United States. A YouTube user named MasterofHyrule decided to illustrate these many differences and put up a helpful side-by-side video to showcase them. Check it out above.
Some things that are minor include transition to worlds from the title screen, while major changes include a boat warping glitch that allowed one to freely traverse the terrain warped to and suits like the Tanooki outfit flying off when hit rather then disappearing.
Source: Kotaku