SNAKE RATTLE AND ROLL

Warp:
To warp to level 3 go to the first island and press B and A.

Warp to world eight:
Try to reach the end of the first level within four seconds.
If you make it, you'll come across a rocket which will allow
you to warp to level eight.

Extra continue:
Make sure you are hit by the last yellow anvil on level four. 
You must be standing on the square in front of the scales when 
it hits you.