List of Super Smash Bros. pre-release and unused content
From the Super Mario Wiki
This is a list of pre-release and unused content for the game Super Smash Bros.
Super Smash Bros. was initially developed by Masahiro Sakurai and Satoru Iwata in their downtime, in a form titled 格闘ゲーム竜王 (Kakuto-Gēmu Ryūō, or Dragon King: The Fighting Game), which lacked Nintendo characters and it was originally planned for the SNES. Iwata, however, felt that the game could not provide the proper atmosphere on a home console without Nintendo characters, and they were soon added and the game was redesigned.
Several more characters were planned to be in the game (Bowser, King Dedede, Mewtwo, and Marth being the only characters that have been specifically mentioned), but were cut due to time constraints. Of these, it is known that Bowser and King Dedede were worked on before being cut. Sakurai also considered adding a brand new character as well as using some unfamiliar characters, but instead decided to focus on more popular Nintendo characters.
Link would have been able to use his shield, and while the feature was almost complete it was scrapped. Link being able to block projectiles with his shield was implemented in Super Smash Bros. Melee.
At one point in development, Sakurai wanted to put in a "time attack" mode, but it was scrapped.
Peach's Castle initially lacked the sign, bridge, and sliding stone block present in the final version. Saffron City initially had a pink and purple color scheme on the rooftop. The bushes and Wispy Woods' leaves on the Dream Land stage were originally a darker green, and the stage also originally had taller grass.
In the character select, the unlockable characters' boxes were originally colored boxes with question marks. In the final game, they are the same as the other boxes, but instead have the characters' silhouettes with question marks over them.
Two early Kirby stages are present in the game's code. The stages have strange elements, such as invisible barriers. A working Dream Land stage can be viewed in the "How to Play" tutorial, which itself can be seen by waiting on the title screen.
There are four unused Announcer voices: "Bonus Stage!", "Draw Game!", "Are You Ready?" and "Final Stage!".  It is also worth noting that "Bonus Stage!" is in the Sound Test as number 198 in the "VOICE" section. Aside from unused Announcer voices, there are also unused character voice clips in the game. Some of these voice clips are used in the second game. In addition to these, leftover Final Smash voice clips for several characters can be found within the game's files.