The content of this list largely comprises of an older list I created for a forum site a long while back, but Ferret75's excellent post detailing potential Majora's Mask achievements influenced me to fine-tune it with a more obscure and challenging approach. As my old list heavily consisted of blatant filler as an excuse to interject puns into the achievement names, this one will focus more on completion and optional challenges than mandatory tasks.
Conforming with the standard, this list will contain 50 achievements adding up to a total of 1000 gamerscore. Descriptions that change after their corresponding achievements are unlocked are notated. The points provided for each unlock corresponds with the estimated difficulty and/or severity of the achievement. Most of the information regarding mandatory achievements will be brief, since they're mostly self-explanatory and obvious to figure out when playing through the game.
If you're reading this post, thank you. I've refrained from posting on the site for while due to a personal dry spell of ideas and lack of direction, so you have my thanks for reading my first post!*
*Well, second if you count my Rock Band Blitz review.
Mandatory Achievements (165)
These are story achievements that cannot be missed on a normal playthrough.
1. That's the Spirit! (5) ~ Capture a Portrait Ghost
This one is for capturing the first Portrait Ghost: Neville
2. Nap Time (10) ~ Encounter a young, crying individual (Captured Chauncey)
This is for defeating the boss of Area 1: Chauncey.
3. BOOm Goes the Dynamite (10) ~ A dangerous threat has been unleashed... (Unleashed the Boos)
This is for releasing the Boos from the Storage Room.
4. Heart of Ice (5) ~ Best a ghost that thrives on the elements (Defeated a ghost with an elemental heart)
One of the more minor tasks in Area 2, this is for defeating a ghost with an elemental heart. This will be acquired in either the Kitchen or the Hidden Room, where a Flash - a ghost with a frozen heart - must be defeated to progress.
5. "The Only Thing We Have to Fear..." (15) ~ Expel the manifestation of fear and suffering in the mansion (Captured Bogmire)
Bogmire, Area 2's boss, must be defeated for this achievement.
6. Things Aren't Going Well (5) ~ Uncover Mario's whereabouts
As the name might imply, this is for entering the well in the backyard and peeking into the Secret Altar.
7. Medalling Kid (10) ~ Complete your elemental arsenal (Collected all three Elemental Medals)
Collecting the Ice Medallion, the last of the three Medals, will unlock this.
8. What The Heck Was He Doing?! (10) - Collect Mario's missing keepsakes
This will be unlocked after collecting all five of Mario's lost possessions. (I'll miss the punny achievement names I had for each one...)
9. Rest In Peace (5) - Fulfill a certain ghost's last request (Captured Madame Clairvoya)
Madame Clairvoya's capture will trigger this achievement.
10. Boo, Get Off the Stage (20) ~ Dissolve a destructive alliance (Captured Boolossus)
Capturing Boolossus unlocks this achievement.
11. Break On Through (5) ~ Restore light to the darkened mansion (Flipped the breaker switch to end the blackout)
During the blackout, the Breaker Room must be found. Hitting the breaker switch unlocks this achievement.
12. Death of an Artist (25) ~ Triumph against the sinister mind behind the mansion's ghosts (Capture Vincent Van Gore)
Vincent Van Gore's defeat will prompt this achievement.
13. Dethroned (40) ~ Expel the ghostly threats from the mansion forever (Beat the game)
Beating the game under any condition will unlock this achievement.
Optional Achievements (156)
These achievements are reserved for tasks that are likely to be completed on an initial playthrough, but are not required to beat the game.
14. Fast Money (15) ~ Capture a swift spirit to obtain lots of money
There are 15 Speedy Spirits found in the mansion. Capture one of them.
15. Oh, Boy! (15) ~ Trap a gold-colored critter that explores the hallways
There are 10 Gold Mice in the mansion. Five are found in the hallways with a 20% chance of spawning, and the other five are found when pieces of cheese are scanned with the Game Boy Horror. Capture one and the achievement is yours.
16. Looking Like You've Seen a Ghost (5) ~ Scan a spirit with your trusty device
To unlock this, you must scan a Portrait Ghost with your Game Boy Horror. Simple as that.
17. An Impoverished Critic (5) ~ Have Luigi examine five objects in the mansion
Using the Game Boy Horror to scan a piece of furniture will prompt Luigi to make a personal comment on the condition of it. His comments are often negative, constantly talking about how fatigued and dusty most of them are. Doing this on five different types of furniture will earn you this achievement.
18. In Bloom (5) ~ Give the bean on the ground a little bit of water
There is a plant in the Boneyard nearby the Kitchen. Using the Water element to hose it will cause it to grow slightly.
19. No Problem, Bud! (30) ~ Take proper care of the plant
Watering the plant after defeating Bogmire will turn it into a flower. Watering the plant again after defeating Boolossus will unlock this achievement, alongside the reward of the Gold Diamond.
20. Chamber of Secrets (15) ~ Enter the Hidden Room
The Hidden Room can be accessed through the Butler's Room on 1F. On the east side of the room, there is a mousehole. Scanning the hole with your Game Boy Horror will cause a vacuum to appear in the hole, allowing Luigi to enter through it into the Hidden Room.
21. X Marks the Spot (15) ~ Successfully access and leave the Sealed Room
The Roof has two chimneys. One chimney has a chest on top of it, but the other is open. Falling through the open chimney will cause Luigi to enter the Sealed Room through the fireplace. That's the easy part, but leaving the enigmatic room requires knowing a certain technique in the game. While the room's door is unbreachable, there is a mirror in the room. Scanning the mirror will teleport Luigi back into the Foyer, unlocking the achievement.
22. Bookworm (5) ~ Read all of the books in the Study
Exactly what it says on the tin. There are eight books in the Study's bookcases, each explaining some of the more ambiguous gameplay mechanics. Just read all of them and the achievement is earned.
23. Mowin' 'Em Down (5) ~ Light up the Courtyard
Eliminate all of the ghosts in the Backyard to light it up. Very easy.
24. Key to Fitness (5) ~ Get some much needed exercise (Acquired the hidden key in the Rec Room)
In the Rec Room (where you fight Biff Atlas), there is a treadmill on the west side. Running on it for about five seconds will spawn a key that unlocks the shortcut on the northeast side of the 1F hallway. Collecting the key nets you the five points.
25. Poster Boy (5) ~ Expose the Boo Poster
In the Washroom on 2F, there's a "MONSTERS" poster. Sucking it up with the Poltergust will reveal a poster of a Boo saying "Get out of here!".
26. Canvas Curse (10) ~ Reveal the Boo Banner
In the Projection Room, the giant canvas can be affected by the Poltergust's suction. Like the poster, suck it up to expose the stretched Boo poster.
27. Big Fat Phony (5) ~ Scare Toad
In the Telephone Room during the blackout, a phone is ringing. When you pick up the phone, the person on the other end asks you who you are. You have two choices: "Luigi" or "Bowser!". Choosing the latter scares him and causes him to hang up.
28. Clearly Off-Duty (10) ~ Talk to Toad in all possible locations in the mansion
Meet Toad in the Foyer, on the second floor Balcony, in the first floor Washroom, in the Courtyard outhouse, and on the phone in the Telephone Room (revealing your true identity during the latter).
29. Tone-Deaf (5) ~ Display your lack of musical knowledge three times (Failed Melody's quiz three times)
When meeting Melody Pianissima, she gives you a quiz on what type of level the music she is playing represents. Getting the question right, will lead to a fight between you two. Getting it wrong will prompt you to try again. Failing three times awards this achievement for your musical negligence.
30. Sleep Tight (1) ~ Get a Game Over
Do I even need to explain this one?
Challenge Achievements (329)
These achievements involve fulfilling specific challenges that encourage mastery of the game's mechanics or knowledge of its biggest secrets.
31. Nice Catch (15) ~ Collect a key without letting it touch the floor
This achievement can be unlocked without much trouble if you know what you're doing. Debatably the easiest method of performing this task is to light up a room that spawns a key on a high shelf (examples include Wardrobe Room, Bathroom 1F, Fortune Teller's Room, etc.). Use your vacuuming skills to snag the key, but be careful, because if you vacuum too excessively the key might hit the ground.
32. Ballroom Blitz (15) ~ Capture a dancing couple of Shy Guy Ghosts without separating them
This achievement requires you to find a couple of Shy Guy Ghosts dancing with each other, removing both of their masks at the same time, and subsequently capturing both of them in one suction.
33. The Big Cheese (20) ~ Scan all five wedges of cheese in the mansion
There are wedges of cheese hidden throughout the mansion. Catching the mice that spawn when they are scanned is not required for this achievement. The pieces of cheese are located in the following rooms:
Fortune Teller's Room
34. Should've Brought Some AAs (20) ~ Defeat all of the ghosts in one room without letting your flashlight turn on
This can be done in rooms that have Portrait Ghosts. Once entering the room, hold B and keep your thumb on it until the room is lit.
35. Total Suckage (20) ~ Capture five ghosts with one suction
This is a very straight-forward description. While this sounds difficult, it can easily be performed in the Training Room.
36. Worth the Wait (19) ~ Find the sound designer's hidden tune (Found "Totaka's Song")
The sound designer mentioned here is Kazumi Totaka. Likewise, the hidden music is his signature tune: "Totaka's Song". This can be found at the "Controller Settings" screen directly before the training exercise in the first 10 minutes or so of the game (note: you can revisit this screen if you select the Training Room in the Lab). Waiting for about three and a half minutes will trigger a musical segway into a funky rendition of the famous tune, unlocking the achievement. As a recognition to its Easter egg status, the point total is irregular, corresponding with the amount of notes in the melody.
37. Can't Resist a Pretty Face (25) ~ Scan all mirrors in the mansion (excluding the one in the Mirror Room)
The mirror in the Mirror Room is not included in the criteria for this achievement because it has no properties when scanned. Other than that, there are 14 rooms in the mansion that contain mirrors. Those rooms are:
38. Tough Guy (30) ~ Win a fight against the mansion's musclebound juggernaut without taking damage (Captured Biff Atlas without taking damage)
A lot of you who have played Luigi's Mansion know how unrelentingly annoying it is to fight Biff Atlas without taking a beating. This achievement is a valuable reward for taking down the roid raging beefcake with enough skill to avoid letting your health drain in any way. Using the treadmill key, saving with Toad, and playing in the Hidden Mansion will help alleviate the difficulty.
39. Olly Olly Oxen Free! (25) ~ Win at Hide-and-Seek without cheating
When encountering Henry and Orville in Area 3, they ask you to play Hide-and-Seek with them. The intended method of winning is to use the Poltergust 3000 to find out which two of the five boxes they are hiding in. To gain this achievement, you must refrain from using the Poltergust and win by hoping for the 1/10 chance that your choices are correct. Trial-and-error by picking the same boxes repeatedly is recommended. The downside is that twins still call you a cheater. The little brats...
40. Making a Break for It (25) ~ Restore power to the mansion within five minutes of the strike
For this one, you'll need to strap your speed-running shoes on. You need to flip the breaker switch in the basement within five minutes of ending your conversation with E. Gadd directly after the thunder strike. You'll need to find Uncle Grimmly immediately and ignore the Telephone Room to stand a chance of achieving this one.
41. Time Wasted (35) ~ Defeat the three mechanical marchers without taking damage (Defeated the Clockwork Soldiers without taking damage)
To unlock this achievement, you must confront the Clockwork Soldiers in Area 4 without taking any damage. These ghosts are almost unanimously considered one of the hardest Portrait Ghosts to capture while remaining in intact condition (even harder than Biff Atlas), so this achievement shouldn't be a cakewalk.
42. Bookled Down (40) ~ Capture a Boo that has 300 HP without letting him escape into a different room (allowing him into a nearby hallway is okay!)
If you've played Luigi's Mansion, you know how annoying the Area 4 Boos are, because they always escape to places that are tedious to backtrack to. Bootique can be found in the Artist's Studio on 3F, meaning that it will likely be the last Boo an average player will encounter. Managing to catch this runt without letting it escape west beyond the 3F hallway or south into the Safari Room gives you this achievement, applauding you for preventing the frustration of backtracking!
43. "One Man's Trash..." (40) ~ Find a rare, dark red object hidden in the mansion (Found a Red Diamond in the mansion)
On the Balcony on 3F, the flattop is surrounded by plants. Watering them will give you money, but there is also something unique about one of these plants. On the top-right corner, there is a plant that, when watered, provides a Red Diamond. There are only two Red Diamonds in the game (the other being King Boo's crown, which is mandatory). Collecting this specific one will unlock the achievement. Just don't get disappointed by how cheap it is.
Completionist Achievements (350)
44. Let's Go Again! (30) ~ Complete the Hidden Mansion
After beating the game once, the Hidden Mansion is unlocked. Beat it.
45. BamBoozled (30) ~ Capture all 50 Boos
Right what it says on the tin. Enjoy the achievement and Gold Diamond.
46. Admirable Collection (30)~ Earn all Silver Portraits
This achievement applies with Gold Portraits, too. To earn a Silver Portrait, you must suck 50 HP out of a normal Portrait Ghost, or keep Luigi's health above 50 HP in a boss battle.
47. Priceless Collection (60) ~ Earn all Gold Portraits
Definitely a challenge. To earn a Gold Portrait on a normal Portrait Ghost, you must obtain a Big Pearl from them, which requires you to drain 90 HP in one suction. For the bosses, you must capture them without having Luigi's health decline below 90 HP.
48. Livin' the Good Life (50) ~ Complete the game with the highest possible rank (Completed the game with Rank A!)
To achieve Rank A, you must collect over 100,000,000G in your ventures through the mansion. This will likely warrant knowledge of gem locations, watering the plant, and collecting all of the Boos. Achievement unlocked, now enjoy your complete mansion!
49. Foreclosure (50) ~ Complete the game with the lowest possible rank (Completed the game with Rank H!)
Rank H is obtained when less than 5,000,000G is collected in a playthrough. To ensure this outcome, avoid loose money, ignore obvious money caches and chests, and focus on catching only the minimum number of Boos. Beating it under these conditions will give you reason to celebrate your new achievement and your well-deserved... tent.
50. "A Penny Saved..." (100) ~ Complete the game with only 5,000G
This is the ultimate achievement. To do this, you must not keep any money whatsoever. The only unit of money that is absolutely mandatory in the entire game is King Boo's crown, which is worth 5,000G (the same amount as a single coin). Completing this will likely require frequent saving and loading, careful positioning with Portrait Ghosts to avoid collecting pearls, and intentionally getting hurt to dispose of collected coins (any other type of money collected will warrant a reset to the last save). Being a masochist would likely help with this one.
This list has gone through a considerable amount of revisions throughout my time working on it, but I'm glad it is finally completed. Here's hoping a trend of these lists continues, as I would really like to see how creative other people can get with them!