The King of Fighters is a wonderful fighting game series, and even if you don't personally much care for it, you've got to at least give it credit for forcing Capcom to shake out of their complacency at the top of the fighting game market and start crafting stuff with more depth like Street Fighter 3 (as well as pushing all other game companies in the market to do a little better.)
SNK kind of locked themselves into some problems by choosing to put out a new installment every year, however. After King of Fighters '98 incorporated all the best elements and characters of the previous entries and finally fine-tuned the series to perfection, the only thing left to do was to come up with something completely new that was just as good or better.
Instead, KOF '99 regurgitates basically the same engine, with about 75% old characters and 25% new, and it all has a very samey feel. It still has the same very solid fighting action as the previous games, but by this point it really just doesn't feel like enough.
The game dumps off series mainstays Kyo Kusanagi and Iori Yagami in favor of a new story that centers around "dark" new hero K' and an organization called NESTS that seeks to take over the world with an army of Kyo clones (Kyo remains playable in the form of two of these "Kyo clones", but Iori is completely gone from the roster except as an unlockable secret in some versions.) K' plays like a fusion of Kyo and Iori, but definitely more like Iori - he isn't the ultimate rushdown character like Kyo was and doesn't have his chainable punch combos. Like Iori, he's the ideal of pop Azn cool, which is basically the ideal of cool in America in the 1980s but with more slouching and more hands-in-the-pockets time (and Azn mullet.) The story also shifts to a more generic manga feel, and the art style to a more cartoonish manga look (though the actual sprites aren't really altered all that much from the KOF '98 iterations.)
The returning roster of characters are basically the most popular series mainstays - the Fatal Fury team, the Art of Fighting team, the Ikari team, the Psycho Soldiers, the Korea team, and hawtties King, Blue Mary and Mai Shiranui. New characters are actually lesser in number - K's new team adopts Benimaru but adds newcomer Maxima (giant cyborg variant on Goro Daimon but with a little less throwing and a little Moar Punching), a rather androgyenous female named Whip joins the Ikaris, midget kiddie Bao tags along with the Psycho Soldiers, Li Xiangfei from Real Bout Fatal Fury jumps in with the Hotties Team, and stereotypical bishonen Jhun kicks his way onto the Korea Team.
The way the new additions join in is due to the fact that the series here swipes a page from the Capcom Vs. playbook and expands each team to four characters; only three can fight per match, and the fourth is designated as the Striker, coming in to perform a limited number of bonus attacks when the Light Kick and Strong Punch buttons are pressed simultaneously.
The returning characters only get the usual minor tweaks, and the new characters are largely a boring lot. Jhun is the only really interesting one; though his visual design is clearly generic bishyness to try to draw in more animu girls, he's actually a fairly complex variant on Kim Kaphwan that can be fun to use. K' just feels like a half-rate version of both Kyo and Iori, Maxima and Li are just boring, and Bao is nearly as annoying as Choi Bounge. The game also leaves off with a new boss, who is about as cheap and annoying as you've come to expect from the series; the catch is, this time he looks like something out of Zoolander, and the combination of his cheapness and ridiculous design kind of ends the single-player game on a sour note.
The backgrounds are decent; they employ the shifting scenery of KOF '98, and while there are some fun ones, Capcom graphically had left SNK in the dust at this point, and they don't stack up to the more impressive stages of Alpha 3 or the better entries in the Vs. series. The sprites are still solid, but again Capcom's vibrant art makes you wish for more; SNK seems still stuck in 1996 at this point. The music is completely boring, and the new characters repetitively yell a lot. You also no longer see your team in the background of each level either.
The gameplay doesn't really have much new to offer either; the Striker system doesn't wreck the game, but doesn't add much to it either, and makes it feel like SNK was really threatened by the Vs. games at this point. All else there is on offer is the Super meter, which is just an iteration of one of the Advance mode in KOF '98, at the expense of the choice of the Extra mode.
While the gameplay is still very solid, it doesn't feel like it does enough as compared to the previous entries, particularly the awesome KOF '98. Instead it's just more of the same with a lesser roster and not-so-good music.
* Gameplay Video