Aborted Arc: Before the retool, a story mode in the vein of The Subspace Emissary known as The Flash of Shadows was plotted out with all of the old roster's characters battling an army called the Cubots. A summary of the first half was posted publicly. The second half was kept under wraps and is presumably lost.

Artificial Stupidity: The earlier demos were criticized for their incompetent A.I., but this was thankfully (or not) fixed.

Brought Down to Normal: Several Final Smash transformations had an attack that functioned like a Final Smash in its own right.

Call-Back:

The first trailer, made in 2007, mirrored Super Smash Bros. Brawl's E3 2005 trailer. A newer trailer, released for v0.9b, was modeled after the same trailer.

Despite the technical limitations of Flash's Palette Swap functionality, they were nevertheless able to successfully recreate the Melee colors of Mario, Link, Kirby, and Donkey Kong as alternate costumes.note all but Donkey Kong's have since been removed.

Downloadable Content: Expansion characters for Super Smash Flash 2 were planned to be supported after the final release, though this has since been scrapped.

Easter Egg: In one demo version, the credits said that the WarioWare, Inc. stage was "Made by Wario. Waa haa haa!"

Surprisingly Creepy Moment:

The 2nd Target Test stage from 2's demo v0.9. It has depressing music, seems to be aesthetically based on Limbo, and overall seems out of place in a Smash Bros. game.

The Super Smash Flash 2 Beta stream at Super Smash Con 2016 on Saturday was very lighthearted and fun, even introducing Bandana Dee as a character. Then, at 2 AM on Sunday morning, the stream unexpectedly started up again with an extremely mysterious video featuring Giygas. This was foreshadowing Beta's inclusion of Devil's Machine, an unlockable stage based on the final battle of EarthBound (1994).

Wallbonking: This was a problem in v0.6 on the Hidden Leaf Village stage, where the wall of the building on the right proved to be irresistible to computer players.

Wheel of Decisions: The Peril Roulette, a now-scrapped new element in the higher difficulties of Classic Mode that spins a wheel to choose something to detriment the player, assist the opponent, or, on the hardest difficulty, both. This was presumably to make up for the notorious-for-the-series impossibility of making a hyperintelligent computer player.