These days, every gaming fan under the sun is aware of the franchise-spanning beast that is Super Smash Bros., but did you know about how it originally took shape under the name of a prototype known as 'Dragon King'?
Smash series director, Masahiro Sakurai, has discussed both this and another unfinished prototype destined for the Nintendo 64 in an interview for Hobonichi's book on Satoru Iwata. Translations of the interview have been shared online by PushDustIn.
According to PushDustIn's translations, Sakurai got to work on a number of N64 prototypes towards the end of Kirby Super Star's development. He began studying 3D tools and animation, eventually designing a prototype called Dragon King (or 'Ryuo: Fighting King', as it was known in Japan), which would use the N64's control stick and all four controller ports. At the time, the game didn't feature 'Special' attacks, but the gameplay "felt like" Smash and was eventually transformed into the original Super Smash Bros. game.
The second prototype discussed was an adventure game starring a robot which would explore a mysterious, underground city. This robot would need to hack into cameras so that the player could further explore the city, and while this title was never released, Sakurai notes that the original Resident Evil actually features a very similar control mechanic.
PushDustIn notes that Iwata handled programming duties for both of these prototypes; work on both continued for some time, but it was ultimately decided that focus should shift toward the fighting game as it would be completed faster. The robot adventure game would have taken "at least two years to finish".
If you're interested in learning more, Dragon King was once discussed in an Iwata Asks interview.