This is a guide to collect every achievement for this second collection. Consider this more like a supplementary guide that should be used alongside other guides. Because there are no passwords, you will likely have to beat the all the games in full to get every achievement.

If you plan to get every single achievement, you will have to beat each game once without turning on Rookie Hunter mode as you must beat Sigma with it off for these specific achievements. Turning it on at any point will void the achievement for that current play through and save even if you turn it off immediately. It also means you can't create a new game plus save even if you played the first run with Rookie Hunter mode. So basically, you have to beat each game on the first run without Rookie Hunter mode on. Aside from that, you can get almost all the other achievements with Rookie Hunter mode on.

Fortunately, cheats don't void achievements for the game, so they should be used to make your runs easier. I will not describe how to beat bosses or obtain all items. There are already plenty of guides out there for that.

Future updates will likely include a cheats section, more detail to get certain parts, and , more details on specific achievements. Let me know in the comments if I should include something for this guide.

Schmooooey has a couple guides ready for your convenience.

https://psteamcommunity.yuanyoumao.com/sharedfiles/filedetails/?id=1449716419
https://psteamcommunity.yuanyoumao.com/sharedfiles/filedetails/?id=1449605244

I would also recommend an Ultimate Armor X run if you don't have Rookie Hunter mode on, because Ultimate Armor will make things significantly easy for you. With X7, focus on upgrading Axl and turn on rapid fire.

General Strategy

When tackling these games, you should either typically beat the games first without Rookie Hunter mode on or have it off to get the complete all the game's achievements. Personally, I do the games with Rookie Hunter off first so that there is no chance I make a mistake later.

Rookie Hunter Run
+Easier to do achievements.
+Pits usually won't kill you, and they respawn you beside it.
+Spikes hurt you only
+You take less damage from everything.
+Life counter maxed out
+Can be turned off at convenience.
+Weapons do more damage overall
+Damage to yourself is nerfed considerably
+Great way to learn the stage layout, boss patterns, and the general feel of the game
+Great for total novices

=You will still die getting squished.
=You will still die from colliding the wall with the bike sections.
=Other reploids can still die or get manipulated.

-Will mark your save file and future new game plus save files preventing you from getting the non-Rookie Hunter mode achievements on those files.
-If you turn it on accidentally, you may have to reset the game forcing you to redo any progress you made.
-It will be harder to purposely kill yourself with it on.
-Not every achievement can be unlocked this way forcing you to do one additional playthrough if you start with Rookie Hunter on first.

Non-Rookie Hunter Run
+Almost every single relevant achievement will be available to unlock allowing you to beat a game with as less playthroughs as possible.
+Gives you the most authentic experience of a game.
+Cheats and other time saving methods won't disable achievements.
+You can purposely die faster when needed.

-You have to watch out for the Rookie Hunter option when pausing.
-You won't be able to easily beat games this way.
-Spikes instantly kill you.
-Pits instantly kill you.
-All mentioned benefits from Rookie Hunter mode are not present.

Now for the achievements, starting with the first game in this collection.

X and Zero have returned, and they must deal with a catastrophe that can literally destroy the world! You also apparently have a team of reploids that appear out of nowhere to help you out.

This game will require you to play through the game twice to get all achievements. There is a good and bad ending route that is chosen depending on whether Zero lives or not.

Go ahead and configure your controls here and proceed with the game.

General Hints

- You should choose X before starting the game since you will have access to the Fourth Armor (from X4) right at the start. X is also more available than Zero in this game. If you are not worried about the Ultimate Armor achievement, you should use the Ultimate Armor cheat at the start. The Ultimate Armor is the best armor for killing bosses.

- If you use choose Zero at the start, make sure to use the Black Zero cheat as that will be helpful in that play through.

- To get parts, you must not play on the easiest in game difficulty, and you have to waste time until you reach 10 to 11 hours. Since Zero starts at a high rank, it is best to get these parts as Zero. To waste time, you must get a game over on the stage and exit the stage. The character you are not going to use to get parts should waste time killing themselves, since dying might decrease their rank.

- If you plan to waste time in stages as well as use Rookie Hunter mode, make sure to turn off Rookie Hunter mode before playing a new game or loading your save so you start off with two lives instead of nine. Having it off will allow to die in pits and spikes quickly. Just turn it on, when you reach the desired time.

- If you attempt to destroy the meteor with the cannon, save before launching the cannon every time you beat a level. If you fail to destroy the meteor, only reloading the save won't change your chances. You will be forced to use the cannon once you get all the cannon parts or your time is up.

- The good ending route will be unlocked if you can destroy the meteor with either the cannon or rocket. The bad ending route will be unlocked if you fail to do both. Its easiest to unlock the bad ending if you use them both at once.

Achievements

Curiouser and Curiouser
Complete the opening stage of any game in both the English and Japanese versions.

You can switch the language mode of a game from English to Japanese at the Game Selection Screen. Complete the intro stage, quit, switch languages, and play the intro stage again.

Out of the Frying Pan
Fire the Enigma and detonate the colony in Mega Man X5.

Launch the Enigma for every stage completed. Reload the save each time if it fails and do the next stage. Completing a stage with the part will increase your chances. You will automatically fire it once you get all four parts (or defeat the left side of Mavericks), or you run out of time. For the most part, success will be determined by RNG. So even if you have the highest chance of succeeding, you might still fail.

The Red One—No, the Blue!
Defuse seven consecutive bombs in Spiral Pegasus' stage in Mega Man X5.

Dark Hold makes this easier.

Insert Tab A Into Slot B
Obtain eight upgrade parts for equipping to armor in Mega Man X5.

You will only get parts when a boss is level 8 or higher. That means purposely wasting time by dying in stages deliberately, playing on Normal difficulty or higher, and having a high Hunter Rank. It is best to get the parts as Zero as he starts with a higher rank than X. The character that won't be used should be the one to kill themselves, as death might decrease ranking. Zero can get all parts starting at 11 hours left. X can get all parts at 10 to 11 hours if you start the first stage as Zero. Black Zero will already have three parts available for him.

After beating a Maverick, you can get a part if you see a + after Life Up and Weapon Part. It doesn't matter which parts you choose, as long as you get eight by defeating all eight Mavericks. You do need to complete stages to build the parts too as they won't show up immediately.

Up, Up and Away
Defeat an enemy while wearing the Falcon Armor in Mega Man X5.

Guide:
https://www.trueachievements.com/a255858/up-up-and-away-achievement

By Your Powers Combined
Defeat an enemy while wearing the Gaea Armor in Mega Man X5.

You need the Falcon Armor to get the Gaea Armor.

You're Quick, Man
Complete Zero Stage 1 without using Dark Hold in MMX5 (cannot be earned in Rookie Hunter mode).

The Ultimate Armor can pass through vertical lasers at the bottom. The lasers will activate if you fall in front of it. The lasers will remain until you die. Use dash jumping to speedily go through the hallways.

The Trick Is Not Minding
Defeat Rangda Bangda W while wearing the Gaea Armor in Mega Man X5


Armor of Light
Obtain the Ultimate Armor from a Light Capsule in Mega Man X5.

You can't use the Ultimate Armor code. You can only get it as unarmored X for the 3rd Sigma stage.

Alright, It's Over!
Defeat Final Sigma W in Mega Man X5. (Secret)


Time Paradox
View all endings of Mega Man X5

There are three endings.

As Long As I Have This Saber
Complete Mega Man X5 (cannot be earned in Rookie Hunter mode).

You can access the final stages immediately by using the cannon and launching the shuttle. You will most likely get the bad ending, so X should be focused on at the start. The Ultimate Armor will help greatly. You can pretty much get any of the endings to get this achievement. You can also do this achievement with easy and slow modes in the game.

With the series ended and Zero dead, X suddenly returns in a new cash grab of a sequel to fight his most dangerous enemy yet, horrendous level design! X with have to deal with crushers, nightmares, spikes, nightmares, donuts, nightmares, and a whole lot of pits to survive this ordeal of a game!

This game can technically be beaten in one whole run through. However, you might want to beat High Max early to get to the final stages faster if you want to beat X6 quickly without Rookie Hunter mode on. Though, even that play through would require some preparation.

General Hints
-I recommend using the Ultimate Armor code at the start. You will kill bosses fast, traverse areas much easier, and overall it is much more helpful than Black Zero. X is also available to use at the start, so he will have much more use for the Ultimate Armor.

-Collecting reploids is optional this game. You also don't need to see every ending to get the achievements.

-Despite having a lives counter, you technically can continue the game indefinitely from the last checkpoint even if you lose all your lives. However, you only get one chance to use the sub tanks.

-You should use the sub tanks when you know you can kill the boss, but you need another health bar to do it.

-Zero can be unlocked by defeating Dark Zero in a special area. The quickest way to get to a special area is by simply going through Infinity Mijinion's stage. The Ultimate Armor makes this easy.

- You can get to the final stages early without beating every single boss if you can defeat High Max in one of the special areas. However, you need to have one special weapon to even damage High Max.

-Reploids that need to be rescued can be permanently lost, so make sure to either leave the screen or catch the reploid before it is taken over. It is better to fall into a pit to save the reploid, than to restart the whole stage again.

- You can't instantly exit a special area even if you beat the maverick of the whole level. If you know that you can't defeat High Max, you have to suicide to exit the stage. It is recommended to do so before the checkpoint before the boss area and with Rookie Hunter mode off. Or, if you really don't need to be in the special area, just reset the game.

Achievements

Wait, What!?
Try falling into a pit in Rookie Hunter mode in Mega Man X6.


Glitch in the System
Encounter all 8 stage-affecting nightmare phenomena in a single play through of Mega Man X6.

You don't need the Maverick's alive for it to count. Seeing the effect counts as an encounter, so you can exit once you encounter the effect. It is best to beat every Maverick before hand. I don't think you need to see both effects for each stage, but I'm not for sure.

Unfinished Business
Have Zero return to the Maverick Hunters in Mega Man X6. (Secret)

Fight Nightmare Zero in one of the secret areas in the Maverick stages. Defeating High Max before Zero will prevent you from getting him.

Ice-Skating Uphill
Defeat an enemy while wearing the Blade Armor in Mega Man X6.

Infinity Mijnion has the part in the special area, Shield Sheldon's part is located through an invisible wall in the bottom secondary area. Commander Yanmark has a part, and going through the fourth totem in Ground Scarvich's stage will give you a part.

Guide:
https://www.trueachievements.com/a255869/iceskating-uphill-achievement

Theatricality and Deception
Defeat an enemy while wearing the Shadow Armor in Mega Man X6.

Guide:
https://www.trueachievements.com/a255870/theatricality-and-deception-achievement

My Ult Is Ready
Defeat an enemy while wearing the Ultimate Armor in Mega Man X6.

You need to use the Ultimate Armor code.

Blackout
Defeat an enemy as Black Zero in Mega Man X6. (Secret)

You need to use the Black Zero code and defeat Nightmare Zero to unlock Zero.

What's Special About SA?
Raise your hunter rank to GA in Mega Man X6.

Defeat Dynamo in the special areas as either X or Zero if you don't get this rank before beating the eight Mavericks. Dynamo won't dissapear even if you defeat him.

Let's Do This Right
Defeat all eight Mavericks before assaulting the laboratory in Mega Man X6.

Just don't beat High Max in the special area. You get the achievement as soon as you enter the first final stage.

I'm Sure It's Over This Time
Defeat Hell Sigma in Mega Man X6. (Secret)


Let's Build a Real Utopia
Complete Mega Man X6 (cannot be earned in Rookie Hunter mode).

Either all the mavericks are defeated or High Max is defeated to unlock the final stages. However, you need to have specific items, upgrades, and weapons to properly beat the final stages.

Special Reploids

There are 128 reploids, but I will only mention ones that have useful parts. I would reccomend going after some of these parts to make the final stages more tolerable. Use this guide by Ed Mak for the rest.

https://gamefaqs.gamespot.com/ps/516512-mega-man-x6/faqs/15379

Amazon Area - Commander Yammark

5 - Iso / Life Recover - You need to do some super-jumping to get this reploid. He's in the far-top-left hand corner of the tunnel after coming in from the surface. He is out of reach unless you use the Blade Armor or Falcon Armor as X. With the ice weapon from Blizzard Wolfgang, you can jump on the ice cube, jumpoff of it, and then quickly dash to the far left corner. He will be next to an Energy Tank. You can also equip speedster and jumper for this as well.

10 - Goken / Super Recover - On the top-left-most platform or ledge on the area after reaching an ice-coloured tunnel. These platforms or ledges are grassy.

15 - Kuborina / Rapid 5 - During the bottom pathway of the tunnel after coming in from the surface, right before the part where you have to ride those mechaniloids to cross the spikes. The reploid is in the fake pit near Yoshimu. He'll be right there close to a Nightmare, so go get the reploid quickly Just in case you can't see pink on blue background, there's a heart tank next to the reploid.

Northpole Area - Blizzard Wolfamg

3 - Ryu / Shot Eraser - This one's at the beginning of the area after the vertical avalanche section. First, you have to gain footing on the ledge at the top right corner. You can do some super-jumping, Up there, he is in the front of the capsule. Watch out for the nightmares that go after him.

6 - Nina / Weapon Drive - This area is only available when you see fire balls falling from the sky. If there isn't, then there will be a couple of cracked ice walls to the right of the area after the after the vertical avalanche section. You will notice a pit of spikes You can use some high jumps to just climb down the ladder and retrieve Nina, but you can also jump down the pit of spikes and dash to her.

14 - Dante / Jumper - In the special area, keep going right until you find a rope that leads down to a floor of spikes. To the left is an opening, go in there. You should now see another floor of spikes. It is a seemingly impssoible huge jump. Shadow Armor or Ultimate Armor will work for X. If you want to do it without the armors, climb back up the pinkish vertical rope, then stand on the ledge at the top. The screen should start to shake and little fireballs will start coming from the sky. Jump back down quicjly to the opening and be hit from one of the fireballs. D. Barrier should be equipped for this . Dash awhile and jump to retrieve Dante.

Magma Area - Blaze Heatnix

2 - Chibon / Buster Plus - In the special area, Chibon will be on a ledge to the right. Count three fire spouts and you'll see the ledge.

14 - Hal / Powerdrive - Take the middle path after the second Mechaniloid battle, he'll be somewhere on the ground in the middle. A nightmare is nearby.

15 - Keiji / Ultimate Buster - Take the bottom path after the second Mechaniloid battle, he'll be in front of the door before the next room.

Recycle Lab - Metal Shark Player

11 - Toshi / Shock Buffer - In the area after you had passed that long narrow path
that barely crushed you with the capsule. He's standing next to a very large pit.

12 - Inaria / Hyperdrive - In the area after you had passed that long narrow path that barely crushed you with the capsule, jump across the big pit. Inaria is standing in front of the capsule.

15 - Dajango / Sabre Extend - In the area that has moving conveyer belts, Dajango is standing next to a heart tank in a small alcove. The alcove has ice covered wall tops and is the last one before the mini-boss.
Central Museum

7 - Tsuki / Speedster - In the third pit in same area after reploid Haven 7. The map will sortof remind you of an upward staircase. Nightmare warning. Before the Heart Tank.

9 - Bro / Quick Charge - Past the special area entrance, you will come across another pit.
Within the gap is Bro. A small nightmare warning here.

16 - Mars / Overdrive - At the end of the special area, Mars should be waiting in front of the boss door. Next to it is a Nightmare.

Inami Temple - Rainy Turtloid

12 - Yui / W. Recover - When it starts raining the fourth time in the level, Yuiwill be on the bottom right, behind some spikes.

14 - Nori / Hyper Dash - In the special stage, Nori will be on the ledge fourth from the top on the left.

15 - Rena / Sabre Plus - In the special area, Rena will be at the top-right corner after a patch of spikes.

Laser Institute - Shield Sheldon

11 - Taiji / Energy Saver - In the special area, there are these two reploids across spikes. Shadow armor, Zero's ceiling dash. Ultimate armor, and/or getting hit for brief invincibility will work.

and/or Break Armor will work.

11 - Taiji / Energy Saver - Right behind Matumary.

14 - Kenz / D. Barrier - Sixth rope from the beginning of the special area.

Weapon Centre - Infinity Nijinion

4 - Paralla / D-Converter - In the section after the first power cable and before the second power cable mini-boss., you'll see a slanting rope with a big pit beneath it. Above the rope is Paralla. Nightmare warning.

7 - Tekk / Speed Shot - In front of the boss's door will be Tekk. A small nightmare problem is around, but it is not a problem.

11 - Metal / Master Saber - Underneath the third rope, from the left, at the top will be Metal. In the spsecial area.

From the series that just won't die, X finally jumps into 3D! But, he is not the main character this this time... Instead we got a new character to be the main character...some kid named Axl.

It should take only one run to beat the game if you answer all the calls from Axl in the intro stage and focus all the upgrade chips on one character.

General Hints
-You should dedicate all upgrade chips to one character. Axl is a good range character that is available at the start. Zero pretty much can use special weapons infinitely.

-You can turn on rapid fire for Axl in the options.

-You should make sure to listen to all the calls from Axl before you complete the intro stage. You can't redo the intro stage after the first time.

-You don't need to have every character listen to Alia's calls in the same spot.

- Consider the secondary character as a 2nd life bar especially in boss fights. Just make sure to switch characters before you die or you lose a life.

-Despite having a lives counter, you technically can continue the game indefinitely from the last checkpoint even if you lose all your lives. You can even save and upgrade your characters before continuing from that checkpoint.

-You should use the sub tanks when you know you can kill the boss, but you need another health bar to do it.

-Reploids that need to be rescued can be permanently lost, so make sure to either leave the screen or catch the reploid before it is taken over. It is better to fall into a pit to save the reploid, than to restart the whole stage again. If you want you can kill yourself to keep the current reploids you already saved.

-You don't need to fight the first phase of Sigma again if you die. You will automatically restart the 2nd phase of Sigma again.

-You don't need to beat the game with every character.

Achievements

Smooth Operator
Listen to all of Alia's support calls in Mega Man X7.

Follow these guides:
https://psteamcommunity.yuanyoumao.com/sharedfiles/filedetails/?id=1455293893
https://www.trueachievements.com/a255877/smooth-operator-achievement
https://megaman.fandom.com/wiki/Alia/Quotes

Beep Boop I Am a Robot
Use Axl's copy ability to transform into five enemy types in Mega Man X7.

Check out this guide.
https://www.trueachievements.com/a255878/beep-boop-i-am-a-robot-achievement

You Got a License for That?
Defeat enemies using all of Axl's weapons in Mega Man X7.


The Exquisite Art
Defeat enemies using all of Zero's techniques in Mega Man X7.


If You Want Peace...
Defeat enemies using all of X's weapons in Mega Man X7.

You must have X unlocked.

Hold My Drink
Complete a stage in Mega Man X7 without switching to a partner character.

Don't switch to the partner. Basically, you have to beat the stage with one character.

Take to the Skies
Obtain all four armor parts in Mega Man X7.

Can only be gotten with X. You can't collect the pieces as Axl or Zero.

Guide:
https://www.trueachievements.com/a255883/take-to-the-skies-achievement

Who Rescues the Rescuer?
Rescue all wounded reploids in Mega Man X7.

You can't let a single one die. Touching an enemy or its projectile will kill them. As soon as they show up on screen, you should rescue them quickly or risk having them die.

Guides:
https://psteamcommunity.yuanyoumao.com/sharedfiles/filedetails/?id=1455199363
https://www.trueachievements.com/a255884/who-rescues-the-rescuer-achievement

It Has to Be Over Now
Defeat Sigma's second form in Mega Man X7. (Secret)


Unstoppable
Use chips to upgrade any one character to maximum in Mega Man X7.

Focus on Axl or Zero, but only on one of. You need 12 chips to max one of them out. There are 16 chips per playthrough. Since X is gotten later, he shouldn't be focused on.

We Haven't Seen the Last of Them
Complete Mega Man X7 (cannot be earned in Rookie Hunter mode).

You have to beat X7 on the first play through.

X, Zero, and Axl are back, and they have to deal with a whole lot of Sigma this time around! Boba Fett also comes back randomly for one last chance at revenge.

This game should only take one run to beat if you use all the passwords. I would reccomend you use all the passwords to save time.

General Hints
-Switch to the 2nd character if your health bar becomes red. That part of the health bar will be recovered when the switched out character is in standby.

--Ultimate Armor X can pretty much defeat every boss easily. However, the boss can't die until it uses it's special attack once.

-You should upgrade your health bar for X first as that compliments well with the Ultimate Armor.

-If you need metals grind in the Metal Valley stage.

-You don't need to complete the game as every character.

-You don't need to upgrade any of the navigators to get the achievements.

-You should probably spend the metals on upgrades first, then reload the save to get all the navigators.

Achievements

Heroism Protocol Engaged
Upgrade X, Zero, and Axl to a power rating of 100% in Mega Man X8.

You need alot of metals. You will also need to collect all the special metals to get the option to buy all the upgrades. The Sigma Blade counts, so you need to input the code and buy it too. You don't need to buy all the general items meant for every character.

Crushin' It
Defeat an enemy using Giga Crush in Mega Man X8

Specific to X's Icarus Armor.

Guide:
https://www.trueachievements.com/a255889/crushin-it-achievement

Overdrive
Defeat an enemy using X-Drive in Mega Man X8.

Specific to X's Hermes Armor.

Guide:
https://www.trueachievements.com/a255890/overdrive-achievement

Strike First Ask Questions Later
Defeat an enemy using Nova Strike in Mega Man X8.

Use the Ultimate Armor code.

Total Eclipse
Perform a double attack as Black Zero and White Axl in Mega Man X8. (Secret)

Use the codes to get Black Zero and White Axl at the start.

Doin' It For Themselves
Fight as Alia, Layer, and Pallette in Mega Man X8. (Secret)

Input all three of the codes, and buy them all in the metal shop. Then just use all three in a level afterwards. You can restart the game if you need the metals back.

It Feels So Right...
Defeat an enemy using the Sigma Blade in Mega Man X8. (Secret)

Input the code, and buy the Sigma Blade for Zero.

Rival Revival
Encounter Vile V four times and defeat him before completing the Gateway stage in Mega Man X8.

Vile will randomly be encountered in one of the levels. The final time to meet Vile will be in the intro stage.

DLN.003
Encounter and defeat Cut Man in Mega Man X8. (Secret)

Use the code at the start. You will encounter Cut Man before meeting the Optic Sunflower.

It's Over, Once and For All
Defeat Lumine's second form in Mega Man X8. (Secret)


Awakening
Complete Mega Man X8 on Normal or higher difficulty (cannot be earned in Rookie Hunter mode).

Use all the codes first thing, play on normal, and proceed with playing the game. X and Zero should be focused for upgrades. Gravity Antonion should be played as the 3rd stage to make sure Vile ends up being the mini boss instead of the spike blocks. Earthrock Trilobyte's stage is a decent stage to grind metals especially using the grinding trick with Axl and the Ice Gatling weapon. Ultimate Armor is your best friend for murdering bosses.

Watch the credits through.

The Saga Complete
Complete Mega Man X5, X6, X7, and X8.

If this is the last game beaten.

Another Day, Another Recon
View 20 images across all four titles, then change the wallpaper to the secret image.

Viewed 20 images for each of the Mega Man X games in the gallery, started one of the Mega Man X games, and changed the wallpaper to secret wallpaper that should have showed up.

They've Hacked Our Comms
Listen to 10 tracks for long enough with the Music Player, and then listen to the secret track.

First complete challenge mode to unlock the secret track called "Give it a Shot (Extended0." Autoplay all the tracks in the Music Player for the Megaman X Legacy Collection 2 section.

Defrag Complete
Blast through the mystery of the staff credits and return to the future.

Play the credits and destroy as much of the names as possible until "RE:FUTURE" shows up in the bottom left corner. The credits play after beating challenge mode so try it there first to save time.

Speed of Light
Complete any X Challenge stage with at least 9:00 left on the timer.

Beat the first fight fast on easy.

Can't Hit Me
Complete any X Challenge stage with no more than 3:00 left on the timer.

Just stall on the first fight on easy. You can defeat one of the bosses to receive less damage.

Try Three on One Next Time
Complete all X Challenge stages.

Do this on easy.

Check out these links for more guides and tips!

http://mmhp.net
https://www.trueachievements.com/game/Mega-Man-X-Legacy-Collection-2/achievements
https://gamefaqs.gamespot.com/gamecube/926372-mega-man-x-collection-2/faqs