Wire:
The Wire is found in Drill Man's stage. After you beat Quint, hop on the Sakugarne and go right as fast as you can. Your goal is the darker-colored column of ground. If you manage to hit it, you burrow into it and it leads you on the path to the Wire. You have basically no room for error here; you must proceed right as quickly as possible.
Balloon:
The balloon is found in Dive Man's stage. After you beat Enker, grab the Mirror Buster and go right as fast as you can. Your goal is to hit the missile in the glass tube area. If you manage to hit it, the glass tube breaks and it leads you on a path the the Balloon. Again, basically no room for error here. You will pretty much have to be sliding any time you are touching the ground.
Super Shadow Man:
You can trigger the final battle against Super Shadow Man in Wily 4 if you make it to Chimerabot #3 without losing a single life. Super Shadow Man is extremely difficult and has no weakness. If you die to him once, you can no longer fight him. Beating him grants you a Yashichi, which refills all health and weapons, and the ?Dagger, an item which makes all of your attacks critical hits. It basically trivializes the rest of the game. If you lose to Shadow Man, you do not get an opportunity to try again.
Secret Item Locations:
You get most of these items by sucking up the target with Dust.
If you suck up the Wire or Balloon, it will not reappear in that location until you get a game over. The Wire and Balloon are probably more useful than these items, so I recommend getting the Wire and Balloon in Dive Man and Drill Man's stages and then getting these items in the Cossack stages.
If you want to suck up a boss, it must be the killing blow.
If you suck up Eddie, he will no longer appear to help you. A gray copy Eddie (made by Wily?) will replace Eddie in the ending if you do this.
You get 5 points for keeping Eddie alive and 2 points for having the Energy Splitter. If you want a perfect score, do not kill Eddie. Killing Eddie also prevents you from unlocking the Mechanical Arena.
*Note: Don't do this!
Result:
Upon completion of the game, you will be given a score out of 100, depending on how well you did.
MISSION:
Worth 60 points. I believe these are free points just for clearing the game.
FRIENDS:
To get 15/15, you must save Rush and Beat in Wily 4, and not kill Eddie.
You can rescue Beat in the final stage by blowing up the suspicious-looking block between Chimerabot #1 and Chimerabot #2.
You can rescue Rush after Wily kidnaps him. He is in the final screen before the Petite Robot Masters in Wily 4. Shoot the suspicious-looking cell.
EQUIPMENT:
Collecting the Metool's Helmet, Super Star, Skull Amulet, Shock Guard, and Trampoline each give you 2 points, for a total of 10, which is what you need for a perfect score.
Getting the Energy Splitter gets you an additional 2 points in this category, but you lose 5 points in Friends, so the overall effect is a loss of three points.
Getting the ?Dagger gets you nothing in this category. Since the ?Dagger replaces the Super Star, it may be possible to skip the Super Star and still get a perfect score if you get the ?Dagger; needs verification.
PLAY STYLE:
To get a perfect score in this category, complete the game in under an hour and forty minutes without revisiting any robot master stage or getting a game over.
BONUS:
Bonus 1: When refighting Toad Man in Wily 3, use Toad on him, and then grab the orb without killing Toad Man. This is worth 1 point.
Bonus 2: Defeat Super Shadow Man. This is worth 2 points.
Bonus 3: On the final escape from the Skull Fortress, if you die three times, the spikes will turn green and become much less damaging, making this segment considerably easier. If you do not die three times, you get this bonus. This is worth 2 points.