Differences between SMB1 and SMB2-J

-Mario/Luigi bounce higher off enemies
-Luigi has different physics (jumps higher, accelerates/decelerates slower)
-Fireworks happen when coin count 1's digit matches TIME remaining 1's digit
-There are some new features like wind, green springs, red piranha plants, poison mushrooms, etc.
-Minor differences in enemy AI that make a big difference in the speedrun (Bowser, cheep cheeps, hammer bros., etc.)
-There are upside-down pipes you can clip into to do wrong warps
-World 9 is accessed by beating the game warpless, and worlds A-D are accessed by beating the game 8 times and holding A when starting the game.