Here is the full list of all 52 Mega Man X Legacy Collection 2 achievements.
Complete Mega Man X5, X6, X7, and X8.
Complete Mega Man X8 on Normal or higher difficulty (cannot be earned in Rookie Hunter mode).
Upgrade X, Zero, and Axl to a power rating of 100% in Mega Man X8.
Defeat an enemy using X-Drive in Mega Man X8.
Defeat an enemy using Giga Crush in Mega Man X8.
Encounter Vile V four times and defeat him before completing the Gateway stage in Mega Man X8.
Defeat an enemy using Nova Strike in Mega Man X8.
Listen to all of Alia's support calls in Mega Man X7.
Complete Mega Man X7 (cannot be earned in Rookie Hunter mode).
Defeat enemies using all of Zero's techniques in Mega Man X7.
Defeat enemies using all of X's weapons in Mega Man X7.
Defeat enemies using all of Axl's weapons in Mega Man X7.
Rescue all wounded reploids in Mega Man X7.
Obtain all four armor parts in Mega Man X7.
Use Axl's copy ability to transform into five enemy types in Mega Man X7.
Use chips to upgrade any one character to maximum in Mega Man X7.
Blast through the mystery of the staff credits and return to the future.
Complete a stage in Mega Man X7 without switching to a partner character.
Listen to 10 tracks for long enough with the Music Player, and then listen to the secret track.
View 20 images across all four titles, then change the wallpaper to the secret image.
Complete all X Challenge stages.
Complete any X Challenge stage with at least 9:00 left on the timer.
Complete any X Challenge stage with no more than 3:00 left on the timer.
Complete Mega Man X6 (cannot be earned in Rookie Hunter mode).
Defeat an enemy while wearing the Ultimate Armor in Mega Man X6.
Defeat all eight Mavericks before assaulting the laboratory in Mega Man X6.
Encounter all 8 stage-affecting nightmare phenomena in a single playthrough of Mega Man X6.
Defeat an enemy while wearing the Shadow Armor in Mega Man X6.
Defeat an enemy while wearing the Blade Armor in Mega Man X6.
Raise your hunter rank to GA in Mega Man X6.
Try falling into a pit in Rookie Hunter mode in Mega Man X6.
Complete the opening stage of any game in both the English and Japanese versions.
View all endings of Mega Man X5.
Fire the Enigma and detonate the colony in Mega Man X5.
Complete Mega Man X5 (cannot be earned in Rookie Hunter mode).
Obtain the Ultimate Armor from a Light Capsule in Mega Man X5.
Defeat Rangda Bangda W while wearing the Gaea Armor in Mega Man X5.
Complete Zero Stage 1 without using Dark Hold in MMX5 (cannot be earned in Rookie Hunter mode).
Defeat an enemy while wearing the Gaea Armor in Mega Man X5.
Obtain eight upgrade parts for equipping to armor in Mega Man X5.
Defeat an enemy while wearing the Falcon Armor in Mega Man X5.
Defuse seven consecutive bombs in Spiral Pegasus' stage in Mega Man X5.