Challenge

Challenge is an extra game mode from Mega Man Powered Up, Mega Man 9 and Mega Man 10 with optional challenges that the player can try to achieve. Those vary by being small stages with their own challenge or an objective to be done in the main game mode.

Mega Man Powered Up
Mega Man: Powered Up has 100 challenges, being 10 for Mega Man (available from the beginning), 10 for each of the eight Robot Masters (the character must be unlocked to play his challenges), and 10 being boss battles with Mega Man (unlocked after completing the game). Although optional, completing all challenges will make Proto Man available as a playable character.

Mega Man 9
If certain challenges in the main game are accomplished, then players gain the following recognition for it.

Mega Man 10
Mega Man 10 has two types of challenges.

Challenge 1
A series of small stages with specific conditions to be completed. Challenges 38 to 88 are unlocked by meeting the specific sub-boss or boss (all varieties with The Keeper and Weapons Archive) in the specific difficult (Easy/Normal/Hard) in the main game.

Challenge 2
Challenges for the main game. Except for Superhero and Headbanging, all challenges can be done with any character in any difficulty.