-Not really a beta, but something often overlooked. Animal Crossing was orignally an N64 game, exclusive to Japan, released near the end of the console's life. The Gamecube version is a port, using basically the same graphics, just sharpened a bit. Also, because it's basically an N64 game, you can let the whole game load at the start, then remove the disk, because at that point, EVERYTHING is loaded into memory.
-If you take an ISO of Animal Crossing: City Folk, and remove all the dummy data, it could fit on a CD. Animal Crossing hasn't really evolved since it's N64 incarnation...
-Originally, Kirby was not going to exist. He was a placeholder for Twinkle Popo, the main character of Twinkle Popo. The devs got so attatched to the guy, that they kept him as the main character, and changed his name to Kirby. There are conflicting reports as to why, but the most common theorys are to pay homage to the lawyer who defended Nintendo during the Universal Studios v. Nintendo of America lawsuit about Donkey kong, whose last name was Kirby, and the fact that Kirby is a vaccuum cleaner, and Kirby sucks.
-Sonic Adventure was originally going to use the Classic Sonic look instead of his more modern appearance we got today. Also, the game looked much more like a Saturn game in terms of graphics during its development, because nobody on the Sonic Team knew how powerful the Dreamcast was going to end up being.
-Mother 3 was going to have a dark as fuck final battle. Instead of just battling Claus, you were basically in Lucas' mind. Here's a video.
http://www.youtube.com/watch?v=82BVe2c6nUs-Kumatora was also suppoed to be the final Magypsy in Mother 3, but they changed it to Fassad. There's an unused animation in the ROM, showing her transformation. Here you go.
http://www.youtube.com/watch?v=yi5e0v9vieA 
