When you get a GAME OVER, hold A and press START on the title screen. This will let you continue from the beggining of the world you died in. You only start from the begging of the world. Not the second or third level of that world.
Fireworks
Pull the flag when the last digit is 1,3, or 6. THat will make you get fireworks.
Hints
To enter weird stuff go to world 1 level 2 the cave. Make sure your super mario. Go to the pipe at the very end of the level jump onto it and bust the block beside the block thats beside the pipe(sorry its kind of hard to put into words im doing my best) and the one beside the block you just busted (the one on the left)now for the HARD part get on the edge of the tube.( VEEERY close to falling off)now jump to your right while holding b. Try to jump thru the block it is VEEERY hard to do (i hope this cheat gets in this website its SOO complecated.my deepest apologies.) if you make it thru the wall you will start getting pushed thru and you will end up in the warp zone go into the first pipe you see and if you did it right you will be in world -1 which is a pretty stupid never ending water level thats not worth all the trouble anyhow. So dont get discoureged if you cant do it. It's pretty dumb. Okay now for the other cheat go to any castle while youre smallgotothewall beside the ax bowser will chase you and try to squeeze you quikly jump and try to land on bowser and the ax at the same time. Forget it im not giving the suprise away. Enjoy!
Multiple Game Genie Codes
Keep in mind that these codes will only work if entered correctly with the NES game genie cheat cartridge. They are very hard to find. I will give you codes to enter ito the game genie to make your Mario playing time more fun.
~One Player Mode Only~
Start On World 8: enter YSAOPE YEAOZA YEAPYA as a code.
Running Super Jump: enter TPZLTG as a code. (note: this means you will jump higher than the screen shows when you are running regular speed, so you go higher.)
~Two Player Mode Only~
Infinite Lives: enter SXIOPO as a code. (both Mario and Luigi will have infinite lives.)
Tweak Music
Using a Game Genie, enter PPPPPP as a code. This will cause the background music to change. Overland levels play the underground level's music, undergound levels play a short intro then don't have music and castles play part of the overland music in a loop.