You can play the 5 villains in any order, since you are transported back to the prison as you finish each one. The order in which you meet them is Copycat, Speeding Spike (Downtown), Sir Rebral, Ratman (under the restrooms) and Crusher.
If you have trouble using the rock, Sir Rebral can be time-consuming. The same goes for Ratman in getting past the rats. But Crusher is definitely the toughest until you get his timing figured out.
(see the related question)
The island after Super Power Island was Spy Island.
BS Super Mario USA Power Challenge happened in 1996.
No, there is no "super strength" on super power island glad to help :D
The subway is Downtown on Super Power Island.
There are no cheats in super power Island.
BS Super Mario USA Power Challenge was created in 1996.
BS Super Mario USA Power Challenge happened in 1996.
Go as far as you can to your right in Super Power Island.
Yes, that is how I completed super power island!
you can't get speed on super power island
There are 6 villains to defeat on Super Power Island.
The force shield is not an item on Super Power Island