Because there are two "one-ups" and coins to be had! :)
beat level 7a
no in new super Mario bros there is no level 0 there is only worlds like world 1,2,3,4,5,6,7,8
It's a cloud level, then it takes you to World 8, which is a lava level .
On the last level of world 2 use tiny Mario to fight the monster and you can get to world 4 with tiny Mario
Complete level six on world eight.
It doesn't have that level only world 1-a
beat the last level in world three
Super Mario World
You need to beat level 2 and 5 as a mini mario to get to them worlds
world six 1 how do you pass it and get on the ledges
no
You have to collect all 3 Koopa Coins in every level of that world.