Here is the full list of all 24 Mega Man Legacy Collection achievements.
Complete all six Mega Man games.
Unmask Mr. X and complete Mega Man 6.
Complete the "ALL ROBOT RUSH (NO ITEMS)" Challenge.
Discover the truth about Proto Man and complete Mega Man 5.
Earn 50 gold medals by completing Challenges.
Earn 50 silver medals by completing Challenges.
Earn 50 bronze medals by completing Challenges.
Complete any Challenge marked with "NO ITEMS."
Complete the Dr. Wily Forever Challenge.
Complete the "ALL ROBOT RUSH" Challenge.
Complete the "ALL APPEARING BLOCKS" Challenge.
Escape the Skull Castle and complete Mega Man 4.
Turn Gamma to scrap metal and complete Mega Man 3.
Take out the Alien and complete Mega Man 2.
Earn 25 gold medals by completing Challenges.
Stop Dr. Wily's plans and complete the original Mega Man.
Earn 25 silver medals by completing Challenges.
Earn 25 bronze medals by completing Challenges.
Earn 10 gold medals by completing Challenges.
Earn 10 silver medals by completing Challenges.
Earn 10 bronze medals by completing Challenges.
Earn 1 bronze medal by completing a Challenge.
Earn 1 silver medal by completing a Challenge.
Earn 1 gold medal by completing a Challenge.