X Challenge

X Challenge is a brand new mode exclusive to the Mega Man X Legacy Collection and Mega Man X Legacy Collection 2 which allows the player to simultaneously fight two bosses (Mavericks or Fortress Bosses) from the SNES and/or PS1 X Games (X1-X6) using X in three consecutive battles. Volume 1 is part of Mega Man X Legacy Collection and Volume 2 is part of Mega Man X Legacy Collection 2. The final match for each of these stages is version-exclusive.

In addition, a brand new armor will be exclusive to the mode which players have option of using X with or without it equipped. Each challenge will have 9 possible special weapons from the six X titles which players will be able to choose between 3 of them and they cannot be swapped until all three challenges are completed. X will also have use of Zero's Z-Saber much like in X6. By not selecting any special weapons before a challenge, a Buster-only mode is activated where X only has use of his X Buster (with the Z-Saber as a sub-weapon). In addition this mode will also remove most of the new armor excluding the Foot Parts, leaving X with just the Air Dash and Hover abilities.

Much like with the Challenges from Mega Man Legacy Collection and Mega Man Legacy Collection 2, each challenge has a clock system and a leaderboard system for players to compete by completing the challenges as quick as possible and within the time limit which is 10 minutes.

Unlike with the earlier Legacy Collections however, players only have a limited amount of lives and start with 2 extra lives in reserve when beginning the challenge, and cannot be restored to full health between challenges (except on Easy Mode). In addition, weapon energy cannot be restored as well.

In Hard Mode only, completing 9-3 will access level 9-4, a secret boss-themed level consisting of both Ultimate Armor X and Awakened Zero. While the player will face this hidden level starting off at 100% with all lives, energy and weapon energy restored, unlike a normal challenge, instead of getting a Game Over if the player is defeated, the game will instead skip to the credits.

List of Challenges

 * Stage 1-1: Arctic Antics - Chill Penguin and Frost Walrus
 * Stage 1-2: Oil and Water - Wheel Gator and Bubble Crab
 * Stage 1-3 (Volume 1): Underground Fight Club - Slash Beast and Crescent Grizzly
 * Stage 1-3 (Volume 2): Tangled Webs - Web Spider and Wire Sponge
 * Stage 2-1: Boom and Zoom - Storm Eagle and Storm Owl
 * Stage 2-2: Jungle Dogfight - Spiral Pegasus and Neon Tiger
 * Stage 2-3 (Volume 1): Undersea Lockdown - Volt Kraken and Shield Sheldon
 * Stage 2-3 (Volume 2): Fly Trap - Spike Rosered and Commander Yammark
 * Stage 3-1: High-Voltage Heist - Spark Mandrill and Bubble Crab
 * Stage 3-2: Glitch in the System - Cyber Peacock and Tunnel Rhino
 * Stage 3-3 (Volume 1): Dopple Gangup - Dr. Doppler and Godkarmachine O Inary
 * Stage 3-3 (Volume 2): Force Multipliers - Vile MK-2  and High Max
 * Stage 4-1: Way of the Warrior - Magma Dragoon and Neon Tiger
 * Stage 4-2: Garden Variety - Spike Rosered and Wire Sponge
 * Stage 4-3 (Volume 1): Storm Warning - Storm Eagle and Toxic Seahorse
 * Stage 4-3 (Volume 2): Warning Lights - Shining Firefly and Armored Armadillo
 * Stage 5-1: Light and Shadow - Spiral Pegasus and Dark Necrobat
 * Stage 5-2: Gestation Operation - Morph Moth and Blizzard Wolfang
 * Stage 5-3 (Volume 1): Naval Engagement - Tidal Whale and Jet Stingray
 * Stage 5-3 (Volume 2): Splash Damage - Toxic Seahorse and Blast Hornet
 * Stage 6-1: Aerial Bombardment - Blaze Heatnix and Blast Hornet
 * Stage 6-2: Of Ice and Fire - Blizzard Wolfang and Burn Dinorex
 * Stage 6-3 (Volume 1): Soldiers' Pride - Colonel and General
 * Stage 6-3 (Volume 2): System Corrupted - Zero Nightmare and Psycho Sigma (Sigma's first form in Mega Man X5)
 * Stage 7-1: Shield Tactics - Armored Armadillo and Rainy Turtloid
 * Stage 7-2: Aurora Bot-realis - Neon Tiger and Chill Penguin
 * Stage 7-3 (Volume 1): Infinity Paradox - Split Mushroom and Infinity Mijinion
 * Stage 7-3 (Volume 2): Buster Alley - Ground Scaravich and Shield Sheldon
 * Stage 8-1: Temperature Critical - Spiral Pegasus and Blaze Heatnix
 * Stage 8-2: Frostbite - Dark Necrobat and Blizzard Wolfang
 * Stage 8-3 (Volume 1): Operation Buzzkill - Morph Moth and Commander Yammark
 * Stage 8-3 (Volume 2): Deep Trouble - Metal Shark Player and Tidal Whale
 * Stage 9-1: Power Saw - Rainy Turtloid and Spark Mandrill
 * Stage 9-2: Sharks and Jets - Storm Eagle and Metal Shark Player
 * Stage 9-3 (Volume 1): Heartbreak and Betrayal - Iris and Double
 * Stage 9-3 (Volume 2): Dynamic Duo - Dynamo and Gate
 * Stage 9-4 (unlocked by completing X Challenge on Hard Mode): The Final Battle - Ultimate Armor X and Awakened Zero

Strategy
Though fighting these three Consecutive battles is tough and that X will only have three special weapons, the trick is to figure out which of the two bosses is the larger threat and just focus on using their weakness against them, while attacking the other one with X Buster since the Plasma Ball can help deal with inflicting minor damage and destroying minor obstacles. The Z-Saber, while effective against Zero Nightmare, should only be reserved for dealing with quick damage and minor obstacles. Occasionally special weapons may help against other bosses, such as Gravity Well against the Blaze Heatnix/Blast Hornet challenge.

Also, if X's health is high enough after completing a challenge, it is possible to complete another challenge to help conserve remaining lives, otherwise just waste the rest of X's life energy if his health is too low to avoid wasting weapon energy.

To get the achievement/trophy Speed of Light from Mega Man X Legacy Collection 2 which requires the challenge to be completed in less than a minute, a great method is to go to Shield Tactics - Stage 7-1, Armored Armadillo and Rainy Turtloid's stage - and bring their weaknesses, Ice Burst and Electric Spark. Electrick Spark's charged form can not only dispose of Armadillo quickly, but it also easily destroys the gems in Turtloid's shell, making him much more vulnerable to Ice Burst.

Trivia

 * Every third stage in X Challenge is different between the two volumes of Mega Man X Legacy Collection.
 * In addition, the bosses of every ninth stage are found outside of the standard eight levels of the games in which they appear.
 * This is the only gameplay feature where X can fight against Iris, a Zero-exclusive boss from Mega Man X4.
 * Oddly, Iris still says, "Forgive me, Zero!" before her battle, despite the fact that she isn't fighting Zero. This is most likely an oversight by the developers.
 * This is also the only gameplay feature where X fights another version of himself.
 * Twelve Mavericks from the first three Mega Man X games do not appear in this mode. Those Mavericks are Launch Octopus, Boomer Kuwanger, Sting Chameleon, Flame Mammoth, Overdrive Ostrich, Flame Stag, Crystal Snail, Magna Centipede, Volt Catfish, Crush Crawfish, Gravity Beetle, and Blizzard Buffalo.
 * Coincidentally, these are half of the Mavericks from each game.
 * Sting Chameleon and Magna Centipede did appear in this mode as copies summoned by Metal Shark Player.
 * In Stage 9-1 (Power Saw - Spark Mandrill and Rainy Turtloid's stage) the battle room is larger than normal. This is to account for the extra room needed to avoid Turtloid's attacks.
 * In both iterations of stage 9-3, after defeating one particular boss, another character appears briefly and uses an attack. They will disappear each time they finish their attack.
 * In Volume 1, if Double is defeated first, Colonel appears to help Iris with any of his attacks.
 * In Volume 2, if Dynamo is defeated first, he'll later appear on the right side of the level to support Gate with his Earth Gaizer Kai attack.
 * Stage 9-4 has a somewhat similar gimmick that depends on which character was defeated first. If Ultimate Armor X is defeated first, Awakened Zero will turn into Black Zero and gain many new attacks (most of which are based on Zero's special techniques seen in X4, X5, and X6). If Awakened Zero is defeated first, Ultimate Armor X will start using new attacks based on special weapons from X6, including Yammar Option and the charged versions of Ray Arrow and Guard Shell
 * Zero Nightmare is slightly altered in X Challenge mode (Normal and Hard); (1) he always has the Thousand Shots attack available regardless of his health. (2) He will use the level 4 variation of Gemurei Kai slashes which he shoots 4 slashes instead of 3, a locked feature in the original game that can only be seen via external cheats/game data modifiers. (3) He has additional laugh voice clips (recycled from intro laugh voice) during ground dash. (4) He can be stunned by jump saber slashes in his initial/dash stance while he can only be stunned by ground slash in the original game.
 * Damage output of several attacks including Sigma's electric spheres, Zero Nightmare's dash contact/Saber slash is modified to be abnormally high (one direct hit of saber slash removes about 1/6 of X's health bar in Hard) - presumably a development oversight.
 * Speed Burner and Strike Chain are nowhere as effective as in original game mobility-wise; because the action system of X is similar to his X6 incarnation and X will not retain increased speed after performing air dashes.
 * The sphere generated by Plasma charged shot is able to damage X5 and X6 bosses but this change makes the main part of charged shot harder to directly hit bosses, in most cases the weaker damage of Plasma sphere will land on bosses first and they won't take damage from the main part of charged shot.
 * The boss invincibility system is changed; bosses will deflect uncharged X buster pellet during invincibility, this makes the rapid uncharged shot strategy against several X1-X3 bosses (especially Neon Tiger) harder to execute and less effective because X can't shoot more than 3 pellets in a row and can't fire new shots until deflected uncharged shots leave the screen.
 * The Strike Chain lock up strategy against Wheel Gator from the original game is not possible here due to the changed invincibility system.
 * In Web Spider's arena, the moment X is allowed to move is later than in the original game; this is probably done in order to avoid the situation which Web Spider being glitched by taking charged Twin Slasher before the fight actually starts.
 * Using charged Strike Chain as finish blow on a particular boss is the only method of gaining life recovery item in Normal and Hard difficulty, but this method is not very effective - because there're only 3 special weapon slots and not every stage has Strike Chain available.
 * It's more difficult to avoid bullet attacks of SNES bosses like Neon Tiger's ground Ray Splasher and Vile's paralyze sparks because the PS1 incarnations of X's hitbox is far bigger than his SNES incarnations.
 * Chill Penguin's blizzard generator now has wind physics and will push X back, like with Storm Eagle's attacks.
 * Metal Shark Player can perform all his available summon variations in hard difficulty.
 * When facing Vile MK-2 and High Max on stage 3-3 in a buster-only challenge (Volume 2 only), the Z-Saber will be given a Purple color so X can use it to attack High Max after he is stunned due to the lack of special weapons. In a regular match it would retain its standard green appearance.
 * The Stage 4-1 description is a reference of SNK's Art of Fighting games, a rival series of Capcom's Street Fighter series.
 * The X Challenge game over/failed theme is a remix of Street Fighter 2 game over jingle.
 * During the Ultimate Armor X and Awakened Zero challenge on stage 9-4, X can also switch between the Fourth Armor, Falcon Armor, and Shadow Armor to perform different attacks before reverting back to the Ultimate Armor.
 * Gate has a special intro voice clip lifted from the voiced dialogue sequence of X6 which he praises X's ability of defeating his star creations and reaching his secret lab in the original game. Player must switch the game language to Japanese in order to activate the special voice clip (Otherwise Gate will remain silent during boss intro as well as most of his actions).