Yoshi Egg - A Yoshi Egg allows Mario and Luigi the ability to ride on a Yoshi. Yoshi can also eat certain Koopas to grant him certain powers. i.e., eating a yellow Koopa allows him to ground pound, eating a red Koopa allows him to shoot three podoboo-like fireballs, and eating a blue Koopa allows him to fly.
Key and Keyhole - If the player finds the key and puts it in the keyhole, they can go to secret levels.
P-Balloon - When Mario or Luigi touches the balloon, they will inflate like a balloon and can float around to get to new areas.
P-Switches - Touching the blue P-Switch will turn Blocks into coins or vice versa. Touching the silver P-Switch will turn all enemies except Lakitu into silver coins.
An insignificant difference is that the copyright of 2001 from the Japanese version changed to 2002 in the international version, as they were released in different years. A significant difference is that in the Japanese version, the logo is detailed like in Super Mario Advance. In the North American and European versions, it is only the logo, having it lazily done. This trend continued in all of the later sequels.
The Japanese version had the Super Mario World text shaded purple and with lighter colors, along with the Japanese text from the old Super Mario World logo. There is also Japanese text on the Mario Bros.
Super Mario World Title Screen
Strangely enough, the graphic designers for the game had trouble installing the Japanese logo in the Super Mario World title screen. They used the International one instead. A few other differences can be seen; the "TM" is bigger in the Japanese version and are from top and bottom. Also, the "SUPER MARIO WORLD" text is recolored. The 2001 and 2002 year difference is also seen.