Adventure

Adventure, more commonly called Adventure mode, is a 1-P game mode in Super Smash Flash, along with Classic and All-Star modes. This mode is very similar to the aforementioned Classic, though it includes platforming segments between each of the fights. Also, in addition to Master Hand, the player will also have to face its left counterpart Crazy Hand at the culminating fight.

As with Classic, the player can set and raise the difficulty level for Adventure before starting, though this will only affect mainly the CPU opponents' behavior, as enemies will act the same no matter which difficulty was selected. Lower difficulties have mild opponents that will barely attack the player whereas high difficulties have more aggressive opponents towards the player. Master Hand and Crazy Hand's HP during the final fight also depends on the difficulty selected. There are five difficulty levels: Very Easy, Easy, Normal, Hard, and Very Hard.

Clearing Adventure with a specific character or under a specific difficulty will reward the player in a certain way if the conditions were met.

Though at one point Adventure mode was confirmed to re-appear in Super Smash Flash 2, there is very little information besides some outdated posts that appeared on early Smash Flash DOJO!!! pages before the latter closure and renovation.

In Super Smash Flash
Adventure in Super Smash Flash is essentially a clone of Classic, containing the same amount of levels, the same bonus rounds and a similar final boss fight. They differ in that Adventure poses side-scrolling levels not seen in Classic, in addition that one of the bonus rounds is harder than the one found in the latter.

Rewards

 * Complete Adventure with on Normal difficulty or higher, then beat him in a match.
 * Complete Adventure without losing any lives, then beat him in a match.
 * Complete Adventure on any difficulty with any character, then beat it in a match.
 * Complete Adventure with any character after having one hour of total play time, then beat him in a match.
 * Complete Adventure with Mario on Normal difficulty or higher, then beat him in a match.
 * Complete Adventure mode with Pikachu and Jigglypuff on normal difficulty or higher, then beat it in a match.
 * Complete Adventure with all 13 starter characters, then beat him in a match.
 * Complete Adventure with, and  on any difficulty, then beat him in a match.
 * Complete Adventure with on Normal difficulty or higher without using any continues, then beat him in a match.

In Super Smash Flash 2
It was initially confirmed that Super Smash Flash 2, like Super Smash Flash, would include an Adventure game mode based on Super Smash Bros. Melee. According to the DOJO!!! update, each level or world is represented as a mini-planet themed with an associated SSF2-in game universe, such as a Mushroom Kingdom mini-planet from the  series, which would have served as the first level of Adventure. With that being said, this information is outdated, so it may not reflect what actually appears in the final game.

Trivia

 * At nine characters, Adventure is the game mode to offer the most unlockable characters to face and the most unlockable features in general out of any game mode in SSF.
 * In early versions of the SSF2 Demo, there were unused files in Super Smash Flash 2 pertaining to Adventure, including a button to start the mode (as seen on the right). These have been removed altogether, as of the Beta version.