Pros: 3D update to enviroments
Cons: Basically feels identical to the SNES game
Well Killer Instinct Gold and Killer Instinct aren't that vastly different. I think it's fair considering that this title merely suggests it's a premium edition of the original. I can't even tell if any new characters are added. It's hardly even relevant for me because I'm not a huge fan of fighting games, and while Killer Instinct isn't a bad game, it's not perfect either, though as much of a fun distraction as any fighter on the N64.
The whole point to any fighting game is to beat up your opponent. Killer Instinct offers a double life bar which basically acts as two rounds, but the health does not refill and there's no "best-of-three". One thing the N64 sorely needed was a street fighter game. The theme of Killer Instinct isn't your typical martial-arts fest, it's just a bunch of hellish critters and a few sexy girls because every game needs a sexy breast count. An undead ninja, an iceman, a werewolf, a skeleton, the roster is funny.
There's not much in the way of modes. You've got the tournament (An elimination sort of fight) the arcade edition (FIGHT YOUR WAY TO THE TOP) and the natural versus mode. Back then fighting and racing games weren't packed with extra content, but this is pretty bare bones. I think this game is unneccessary for two reasons. The first is that it's basically Killer Instinct, and the second is that the updates to the graphics do nothing to make the game full-3D. Sure they're updated, but the game's not significantly different from the SNES version in the visual department, which is the only real place it could be different. The cast of characters also seems to be the same. And without a moveslist guide or something, figuring out the special moves in this game is almost impossible. It's basically built like Mortal Kombat, but it's still pretty fun with huge combos and special moves that let you do all kinds of things.
So yeah. The game could've added a whole lot more than it does, but it still works. The only thing I can really say I don't like about it is that it just doesn't add much. And the graphics are nice, the backgrounds are 3D but the characters themselves are just sprites, and while more detailed they don't necessarily look better than the SNES game's, they're just bigger. The SNES could pull off some great textures in its time so it's really hard for the two consoles to go toe to toe in that area. What I will say is that this is still a really fun fighting game but I prefer the SNES version, and while neither are my favorite fighting games, they're both totally worth getting into.