Wrecking Crew/Stages 1 - 10

Stage 1
Use the door to trick the enemy wrench into passing to the backside of the stage where he can't hurt you. Then take as much time as you need to make the M·A·R·I·O letters appear in the correct order to earn your first extra life, before clearing the stage.

Stage 2
Consider dropping down and destroying the bomb between the two breakable ladders first, before climbing back up and destroying the remaining walls from top to bottom. Just remember not to stand near the bomb when it explodes or you will be sent down to the floor below.

Stage 3
Once again, complete the stage from the top to the bottom. The single enemy wrench shouldn't give you much trouble, as it should drop harmlessly to the floor before it can threaten you. Just be careful when you drop from one ledge to another, and make sure you fall in the right direction.

Stage 4
This is the first stage with a Golden Hammer opportunity. It's difficult, but not impossible, to get both the M·A·R·I·O letters and the Golden Hammer, so it's easier to focus on one or the other. There are two enemy wrenches here. It's in your best interest to keep them together and moving in the same direction. This will minimize the threat they pose to you.
 * Golden Hammer:Destroy the lowest bomb, and then strike the left bomb on the fourth level with the fifth swing of your hammer in order to destroy the target bomb third and reveal the hammer.

Stage 5
Quickly run to the right side by the barrel, and then one by one, destroy each ladder from the right to the left. Avoid each wrench as they fall to the ground.

Stage 6
In this stage, it is quite possible to get both the Golden Hammer and the M·A·R·I·O letters. Keep an eye on the two wrenches and keep them moving together as close as possible. You can capture one, maybe both, by knocking out the beam below the center barrel as they are about to walk past the beam. Note that you will be unable to destroy the panel in the middle of the stage if you destroy both ladders on either side of it.
 * Golden Hammer:Destroy the two bottom bombs, and then destroy the left bomb on the fourth level with your third swing.

Stage 7
Spike is both the problem and the solution to this stage. If you don't move quickly enough in the beginning, he will destroy one or both of the ladders. Climb up one immediately. When you do, Spike and the enemies will climb up as well in pursuit. When you get to the top, destroy one wall and stand in front of the other. Spike should strike the wall and send you to the bottom, passing the enemies. Then hit the closest bomb to the destroy the ladders.

Stage 8
This stage will introduce you to the pattern-following eggplants, who take every opportunity to climb up or down every ladder that they encounter. When the level starts find a safe place and wait for all the eggplants to fall down to the bottom of the stage. Then climb to the top, and take out every ladder from the top to the bottom, crossing from one side of the screen to the other in order to strike the ladder on the opposite side before descending to the next level. Time the destruction of the lowest ladders so the eggplants won't interfere.

Stage 9
This is another stage that you'll want to tackle from top to bottom. It's also difficult to get both the M·A·R·I·O letters and the Golden Hammer unless you're careful and count your swings. It's possible to trap the enemies in the barrels at the top, but you have to risk luring them up there, and you have to watch out for Spike. Be careful not to destroy both ladders leading up until you've fully cleared the floors above.
 * Golden Hammer:Break the two bombs at the very top, and then hit the right bomb on the ground level with your eighth swing.

Stage 10
Although there are two eggplants, no part of this stage is particularly difficult. Try to preserve the two long ladders as long as possible, especially if you are going for both the Golden Hammer and the M·A·R·I·O letters, and then deal with the remainder of the stage at your own speed. You'll have to knock out the beams supporting the walls near the higher eggplant. Let him fall off the ledge as you continue to demolish the stage. It's possible to trap the eggplants in the lower left corner, but be careful you don't trap yourself as well.
 * Golden Hammer:Destroy the two bombs at the top, and then destroy the right-most bomb near the top with your seventh swing.