Wario Land 3/West sector

W1: Desert Ruins
You can reach W1 after collecting the pieces from the gray chests at N2 and N3.

The gray key is located in a building to the right of the start. In the closer room, you should see the key above the room's exit. Crouch-jump from the topmost platform to reach the key.

The gray chest can only be reached during the day, and is in the next building entrance. When you enter, head to the bottom of the room, getting past the enemies by any means; if you get hit by the hammer, try to bounce between the purple bricks if possible. The chest contains an upper half of a magic scroll

The red key is located to the left of the staring location, where you jump across the platforms. Enter the first building, and you'll be quickly attacked by having a doughnut thrown at you. When it wears off, break the right walls, climb up and run to the left.

The red chest can only be reached during night time, and is in the building to the left of that one. As you climb up, you'll notice that you can't jump off ladders. Instead, let the robots to your left push you off instead. The catepillars will try turning you into a string ball, causing you to fall back. The chest is at the end of the run, and gives you a lower half of a magic scroll.

Gold coins

 * 1) During night time, there is an empty sand pit to the left. Break open the purple bricks on the left, and go through.  When you see two green pillars, break through them to collect the coin.

W2: The Volcano's Base
You can reach the area by the Gray and Red chests from W1, when the paper scroll dispels the tornado.

The rolling jump is necessary here. To roll, press on a ramp, then  to jump. Your first rolling to unlock the gray chest is to the right of the entrance, on the ramp just before the red pipe. If you jump correctly, you should roll into the room containing the gray key.

To reach the boss guarding the gray chest, start the roll on the same platform, and jump at the last possible second. Jump to run along the top of the platforms, but drop down to break blocks to the right-most pipes. To defeat the boss, avoid the hammers while using a body slam on the blinking segments. When all three segments are destroyed, attack the boss directly when he turns blue. Once defeated, a hammer-platform will appear, allowing you to reach the chest. Failure causes you to take a different route, and requires you to challenge the boss again.

The gray chest gives you a blue trowser powerup, and allows you ground pound. It gives you access to a new area in N1 and N3.

Just right of the entrance is another ramp you can use, where you go through a door. The door leads to an up ladder, where you have to dodge enemies poking out of the wall. Head up the pipe to reach a conveyor, and an alternate path if you can't making the rolling jump to reach the gray key (however, you still need to do so to collect the key.)

Music coins

 * 1) Do a rolling jump, just to the right of the start.  Instead of following the ground, hop one platform up.
 * 2) There's a conveyor belt.  Even when the conveyor is idle, you can do a jump to land on a platform containing a coin.
 * 3) When doing a roll that would normally reach the boss, perform the final jumps along the upper platform.
 * 4) At the boss fight, either get hit and spring to the top, or break the wall to the right to collect the music coin.