Strike with all your might puzzle?
To get past the strike with all your might squares use the steel shoes and tackle belt and ram into it.

Secret characters
To do this cheat you must have killed all four commanders. When you have done this go to the locations of the first three commanders (Water commander, Electro commander, 3rd Commander) then you will have a chat with them then fight! You also get an extra health point!

Location of the final commander
In the Desert Zone go right of the monster who wants to play it. You will see a cave entrance, enter. Jump over the gaps to your left. Then dodge the arrows and go left. Go South throw a speed bomb on the circle, it will crack. Go up. You will see a rabbit. Dodge it. Go left. Use the wings to dodge the boulders. Then go SW. Go down and put a bomb next to the circle. Do the same thing again but quikly go right. Before the blue block goes up. Use wings and go down over the gap. Go right. Up dash shoes then quikly wings. You should not be hurt. Go down. Go right. Get out a normal bomb and remote control. Put a bomb down near the circle. Go through the spiral. When you come to two squares, detonate the bomb. Go down. Go left. Use homing bombs against him.

3rd commander
Go NE of the dragon, then hit down the totem poles with the hammer, go right. Go up and left. Jump over the gap, then put a bomb down next to the circle. When it blows up use the shield to stop the arrows and walk back. Go SE and you will see another circle, blow it up, then go down. Jump over the gaps, where the skull is, then go left. Use the power bracelet and move the rocks so that you can go past(to the left) you will be in a room of spikes, instead of going NW go SW and then jump over the gaps and evade the rocks, you should make your way to the right. Now you can see him. Use homing bombs on him, it won't hit him every time but be patient!