Battletoads is a video game by Rare Ltd. created to rival the Teenage Mutant Ninja Turtles games. The first game was released for the Nintendo Entertainment System in 1991 and was followed up with sequels released over the ensuing years for GameBoy, SNES, Megadrive / Genesis and Arcade. [Info from Wikipedia] A proto for a GBA version of Battletoads was discovered in the collection of cancelled RARE games that transparentjinjo has uploaded on his Youtube Channel.
The game was only in development for a few weeks, and everything from character animations and enemy AI to sound effects is a placeholder.
The character design was the result of merging the sometimes conflicting ideas of the original Battletoads artists, who were now in director or lead positions on other teams.
Even the main game design was not fixed at that point. Team instructions ranged from “make a shiny clone of the NES version” to “do whatever you think is best” to “everything cool will have to wait for an Xbox version”.