After you've beaten the game once or twice, this is not a particularly difficult achievement to obtain. Make ample use of your special weapons to finish stages quicker, particularly Black Hole Bomb and Jewel Satellite. The former will kill enemies that are otherwise unkillable (i.e. underwater mines, ground sliders) and the latter will make quick work of weaker enemies while you focus on platforming.

If you feel you've taken too long on a stage, reload your previous save and try again. Keep in mind you will need to play through Wily's castle in one sitting though. If you are around the 30 minute mark after beating all 8 stages, you're in good shape with plenty of leeway.

Also not as hard as it sounds. Stock up on plenty of lives as well as an Eddie power-up. Eddie helps because he will most likely drop an energy pellet/ball or two when you're in a pinch; think makeshift E-tank. If you're low on life during a boss fight with no way out, just die and you will respawn outside the boss door. If you lose all your lives, you can just continue and replay the stage until you beat it.

For the Robot Master weakness list, refer to this thread: here

Also these seem to be the most effective weapons against the bosses in Wily Castle:

Stage 1 Boss -> Plug Ball or Mega Buster
Stage 2 Boss -> Tail: Laser Trident or Mega Buster, Belly: Laser Trident or Tornado Blow, Head: Laser Trident or Black Hole Bomb
Stage 3 Boss -> Black Hole Bomb
Wily Machine -> First form: Mega Buster, Second form: Concrete Shot or Mega Buster, Final Form: Plug Ball or Hornet Chaser

The only enemies you can kill are bosses and mini-bosses (the dragon on Magma Man's stage, the elephant on Concrete Man's stage, the Boulder on Jewel Man's stage, and the Flower Clock on Hornet Man's stage). You can kill enemies that a boss releases such as flames, hornets, and missiles. You will need to utilize the brief moments of invincibility after you get hit to progress in the game.

Stock up on shock guards, E-tanks, and Beat calls to make your life a little easier. The 1/2 damage power-up should also be used when necessary (Jewel Man's stage or Wily Stage 3 are good examples). Utilize Rush Jet and Rush Coil to bypass some of the more difficult areas.

During the gravity sections in Wily 3, stay mostly to the left of the screen and use Plug ball to navigate. This way you don't accidentally kill something (like the last grabber in the final gravity section with the M tank). For the area with the green turrets, you can purposefully fall down the chasms to force Beat into carrying you around. Use this opportunity to soar over the turret but be quick about it as it doesn't last long. You can also purposefully get hit by the cannon shot and use the invincibility to progress.

Personally, I did this section using mostly the Rush Jet to navigate between the turrets, the spikes, and the lone sniper joe.

First, go through all 8 stages without using ANY special weapons. This includes Rush Coil and Rush Jet (they count as weapons). You must only use the Mega Buster.

When you get to Wily's Castle, follow this simple outline:

Remember, try not to use the weapons required to progress more than once on each screen unless I say otherwise or you risk not unlocking the achievement.

Stage 1 - Use Tornado Blow to pass the first lift and the lifts in the room after it, then use Rush Jet once to clear the next section. Later, clear the first magma fountain with Rush Coil. On the next screen, use Rush Coil as soon as you leave the ladder, aim Mega Man onto the 2nd ladder from the left when you catapult off Rush. Use Rush Jet in the room with the bed of spikes after the pink teleporter room.

Stage 2 - Use Laser Trident to destroy the first block at the beginning of the stage and the next block near the spikes. Use Rush Coil or Concrete Shot to get up to the ledge with the Sniper Joe in the first room with the projectors. In the underwater portion, take the upper path and use Laser Trident 3 times to break the 3 blocks along the path to the next ladder.

Stage 3 - You won't need any special weapons on this stage.

Stage 4 - Use Concrete Shot to block the only impassable laser and utilize it as a stepping stone to continue.

You don't actually need to beat the entire game five times from start to finish. You can load up a save right before Wily's Castle and finish the game 5 times this way to unlock the achievement.

You will obtain this simply by playing the game. If you're in a hurry to get it, go to Plug Man's stage and activate Jewel Satellite in an area with the respawning cylinder enemies and leave it until the achievement unlocks.

This achievement requires you to be thorough. Some enemies must be killed with special weapons which you may not have the first time yougo through a stage. Nearly everything can be killed with either a Black Hole Bomb or Tornado Blow. In particular, don't forget to kill:

• The floor sentries in Jewel Man's/Concrete Man's stage (Black Hole Bomb)
• The mines in Splash Woman's stage (Black Hole Bomb)
• The sparks in Plug Man's stage (Jewel Satellite or Black Hole Bomb)
• The grabbers that drop from the ceiling in Galaxy Man's Stage
• The dragon mini-boss's flames (Tornado Blow or Black Hole Bomb)
• Anything a boss shoots out (i.e. missiles, fish, hornets)

In Hornet Man's stage, the flower pots that shoot out different types of floral missiles are worthy of mentioning. Make sure you destroy each type of missile. I'm not sure if these count, but better safe than sorry.

To me, the easiest boss to do this on is Hornet Man with the Magma Bazooka equipped. When he launches 3 hornets, aim the bazooka to hit them all in a single shot then simply jump over him as he runs across the screen wihle unloading charged shots at him. Rinse and repeat. Other easy bosses include: Splash Woman, Galaxy Man, and the first Wily Castle boss.