Super Smash Bros. for Nintendo 3DS/Walkthrough

Unlike Super Smash Bros. Brawl, there is no story mode in this game. Instead, players wishing to "complete" the game should aim to unlock all of the characters and stages and complete all of the challenges.

Unlocking Characters
Because this is a portable game, character unlocking is much easier to do here than in previous iterations of the series. Characters can be unlocked by completing a certain amount of fights. After that match is completed, you'll have to win a one-stock match against the character to be unlocked to make them playable. An easy way to complete the match criteria for a desired character is to suicide the amount of matches required so the real fight to unlock the desired character takes less time to get to. Characters grow higher in level the more the player unlocks them, although their level is not displayed when fighting them to unlock them, e.g. Ness is Level 1 and Jigglypuff is Level 9, with the other characters falling in between. Match amounts listed here are based on match total, i.e. a new character could be fought potentially every 10 matches. Here are all of the characters and their respective unlock match amount:
 * 10 Matches - Ness
 * 20 Matches - Falco
 * 30 Matches - Wario
 * 40 Matches - Lucina
 * 50 Matches - Dark Pit
 * 60 Matches - Dr. Mario
 * 70 Matches - R.O.B.
 * 80 Matches - Ganondorf
 * 90 Matches - Mr. Game & Watch
 * 100 Matches - Bowser Jr.
 * 110 Matches - Duck Hunt
 * 120 Matches - Jigglypuff

Unlocking Stages
Stages are unlocked by meeting the following criteria. Many of them require the use of a specific character.
 * Magicant - Unlock Ness
 * WarioWare Inc. - Unlock Wario
 * Pac-Maze - Use Pac-Man's Final Smash (can be done in Training)
 * Dreamland - Use Kirby's Final Smash (Can be done in Training)
 * Balloon Fight - Use Villager in regular Smash 3 Times
 * Mute City - Win 3 Smash Matches with Captain Falcon
 * Flat Zone 2 - Unlock Mr. Game & Watch AND unlock the second page of challenges

Challenges
By selecting the "Challenges" option on the game's Main Menu, there will be one, two or three pages of challenges, depending on how many the player has completed. Each challenge is completed upon completion, even if they are not visible on the page. When a challenge is completed, it will unlock one hint to complete challenges in all tiles adjacent to the challenge completed (not diagonals). Challenges unlock custom moves, stat boosts, Smash Run Equipment, and Mii Clothing & Headgear.