KAGKAL: unbelievably fast goombas

NNAIKE: all power ups and stars kill you

ILOVET: Mario's mouth opens and closes like Pac-Man when he walks

VILLGI: Mario walks backwards

IONATX: Beetles replace goombas

TXEPAG: weird bricks, more fire flowers in some worlds (1-2)

STAGEO + SPEPNY: extra difficult (koopas have hammers etc...)

KOYNAN: no sound when Mario jumps

OPASSE: 1up mushrooms are now power ups

AKEOIP: weird level

VELITT: power ups disappear when hit, very few enemies

OVILLV: when you shoot a fireball, Mario makes the motion, but nothing comes out

GALLSS: when you hit a 10-coin block, only one coin comes out

SONETX: you control the demo

OKENGX: really weird

EKEOTO: invincible

EOXNTI: weird sound FX - coins

AOXNTI: another weird sound for coins

PETEEE: no background, just foreground

TOSXUN: The screen scrolls along with you and part of it disappears. I can't describe it.

EGENIE: Mario skates

XGONLY: Music starts and stops

AXEAXP: backgrounds change colors

IENTIA: 1UP mushroom floats in air

VXATSA: you see the enemies left of your screen when they're really where they should be

OVEKSX: when you stomp enemies, they die but keep on moving

TVASNA: you appear invincible when you get a star, but you can still get hurt

USXEOX: when you hit a block, the block stays unharmed, but the thing inside still comes out.

ESTONE: The pipes you can go down look normal, the others look screwed.

XESTON: Mario looks like Luigi

VOIGEP: Enemies go through pipes, power ups fly to the left

PKONTX: When Mario faces left, he looks normal, when he faces right he looks weird and he can go behind background

VOULOS: Nothing comes out of any of the blocks

OPOISO: cannot be harmed by enemies but you can still stomp them

TOUSSA: You cannot stomp goombas or you'll turn small or die

NOKEAG: Some power ups and stars give you 1ups, hitting red koopas makes weird things happen

OLUNTE: Appear big when you run

XANOPO: no time

TOANPX: Mario is crazy!

KEKAKE: no backgrounds and foreground

INTOAS: weird level, but it works

KYOUGK: Mario falls left instead of right on flagpole

TXEEON: time resets itself to 409 when it reaches 400

SEIING: when Mario hits a block, it becomes nighttime

STAPTO: no music

SEPUEG: when you hit the 1st mushroom block, coins fall from the sky, but you can't get them

SPEPNG: weird level

POPPOK: No Clouds

PSTIOO: Every Enemy Hit Is Worth "1 UP"!!!

PZZONO: Go down any pipe

ZEEOPO: 50 extra seconds

IVYENO: all enemies look like Koopa

PINAAO: Move in pause

SSASSA: Always starman

YAZYIG: Random teleporting

PAZSNO: Always have fireballs

PIGNAX: Invisible

EATSSY: Walk through things

OOTAAA: strange effects

AAAAAA:strange effects

POTEXX: Things turn to 1/2 when hit

TIKOAO: Swim without water

EVYIVY: Everything bounces

OPKOPK: Scenery in sky!

IAGPSK: Warp to 4-1 /w/ no Lakitu (Yeah!)

PIGPEG: World with no enemies or elevators!

PAZSNO You can always throw fireballs

ZIGGYY: More enemies

SKIINO Enemies don't die