That first Klobb fact is dead-on accurate, but I'm not too sure the others are worthy of their own DYKG.
GoldenEye was a beast of a game; easily qualifying for one of the top first person shooters of all time, if not
the best. Multiplayer was a blast.
A couple of years ago I found a great, very professional website full of in-depth easter eggs. It's long gone by now, but my personal favorite was the All Bonds cheat. At one point in the development of the game, you were supposed to be able to play as Sean Connery, Roger Moore, Timothy Dalton and Pierce Brosnan (but no George Lazenby) in multiplayer. Unfortunately, Rare took them out; except for Brosnan, of course. The general theory of why they were taken out was because of legal issues, although it was never explained by Rare in detail. Probably the best evidence for the cheat actually existing is that you can see Sean Connery in one of the multiplayer screenshots if you look in your GoldenEye 007 instruction manual that comes with the game. It also probably helps that Rare officially acknowledges that it exists, but whatever.
If you use a Gameshark, you can find their multiplayer portraits in the game. The textures for their suits and faces were also still in the game and made available with a bunch of tools/ROM editors, but the models were gone. It's very interesting, I would have loved to play as Connery versus Moore.