Super Smash Flash 2 Demo/Version 0.1a

Version 0.1a was the first playable version of the Super Smash Flash 2 Demo, announced on September 24, 2007 and released on December 25 the same year. It introduced the first four playable characters,, , and , along with Test Stage 1, Test Stage 2, and  (which was referred to as "The Battlefield"). As the first primitive build of the game, there were a number of significant fundamental differences and flaws with it compared to most recent versions.

Menu
The title screen was a simple gradient stating the version number, which would remain until v0.6. Pressing "Play" would take one straight to the character selection screen, where the icons of the four playable characters were visible and surrounded by 39 unselectable icons, which represented the former roster plan. Options were accessible above the character icons, but at the time, the only options available were to adjust the time limit and damage ratio. Stock had a space on the menu, but was unable to be adjusted.

Mechanics and physics
The primitive controls of v0.1a were notably different from the official Super Smash Bros. games. The most immediately obvious was the cumbersome method of performing a forward smash attack; if one tried to perform one the normal way, by pressing forward and attack simultaneously, a dash attack would be performed instead. In order to perform a forward Smash, the character had to crouch first. There was no dedicated Shield button; shielding was instead executed by pressing the Down button twice. As a consequence, dropping through platforms was, at the time, impossible. As Super Smash Bros. Brawl was not yet released, the Smash Ball, based on its appearance in the Brawl E3 2005 trailer, behaved very differently from its later counterparts. Rather than moving around the stage, it stayed in one place and could be picked up like a normal item instead of needed to be broken. Furthermore, a character's Final smash was activated by pressing Shield, Standard Attack, and Special Attack simultaneously rather than the Special Attack button alone. Chargeable special moves, such as Super Fireball, Demon Fang, and Getsuga Tenshō, could not store their charge; cancelling them required firing the attack early by pressing the Standard Attack button. The aerial attack system had yet to be perfected. Back aerials did not exist yet, instead, turning the character around to perform a reversed forward aerial. Furthermore, Forward aerials halted any horizontal momentum, sending the character falling straight down. Tilt attacks did not yet exist, likely due to difficulties at the time figuring out how to incorporate them. Jumping, like shielding, had no dedicated key, instead performed by pressing the Up key, like the Tap Jump function in later versions. This resulted in all characters' up aerials and up smashes being one and the same. Multiplayer was not possible yet, despite multiplayer mode being available, and also, the only one mod to be available. Other players could, technically, be set to human control, but doing so would render them immobile.

Notable glitches and bugs

 * Fighting a Level 9 CPU will result in said CPU jumping aimlessly, CPU Kirby in particular consistently rising past the upper blast line and self-destructing.
 * Attempting to perform an Up special move without jumping, which was possible by holding the Up key while landing or during an attack, will result in the move bugging and failing to take the character into the air. Final Cutter in particular would fail to activate entirely, Kirby merely appearing to pose with the sword without attacking.
 * If a projectile is onscreen at the end of a match, it will remain onscreen in the character select screen and even the next match, though without a hitbox.
 * An inaccessible Smash ball would always spawn at the top-right corner of the stage, and fall down aimlessly after the end of the match.