The 6'4" Frenchman carries a massive 82" reach and several titles in kickboxing, savate and Muay Thai, yet has looked mediocre on the feet against all but the lowest level heavyweights. How can it be that a man with such a respected Muay Thai career could struggle on the feet against men like Matt Mitrione?
There is absolutely no denying that Kongo was incredibly skilled in his kickboxing career—the few videos that exist of it make him look sublime—but they highlight the errors which still plague his game and have been amplified to make him look so middling as a striker in the UFC.
What Kongo suffers from is the fate of any kickboxer who moves to MMA—he lacks the wrestling pedigree or ability to play guard to be able to throw kicks with impunity. Anytime Kongo throws a kick he must constantly be aware of being taken to the mat.
Against good grapplers Kongo will fake kicks, but never actually throw any. Against Frank Mir, Kongo faked a couple of kicks which made Mir back up, but then proceeded to do nothing and Mir simply steamrolled him.
Kongo's second great weapon—the clinch—also falls apart against competent wrestlers and indeed opponents who have trained to shake off his blanketing tactics such as Mark Hunt, who easily maneuvered himself off of the fence when Kongo went to the wall and stall.
The downfall of any great striker moving to MMA is that if your kickboxing game is not solid in the punching department you have no areas of the fight in which you are the dominant party.
It is simply easier to learn to sprawl if you have the boxing game to be able to keep both feet on the ground throughout the fight, and you will fair far better than most strikers moving to MMA. If kicking is your bread and butter, then you move to a sport where a mistimed kick, or even a perfectly connected kick can mean being put on your back.
Kongo does not have a solid boxing game, which is even more of a shame because of his arm length and could be a real force in his division if he could simply use it. Because of Kongo's love of bouncing footwork and need to kick fast he stands bolt upright at all times, and this carries over to his punching attempts.
A solid boxing game also serves to set up the kicking game, as the opponent can be forced to cover with a combination and then kicked as he is shelled up. This is Dutch kickboxing 101, but Kongo has never set his kicks up well, and he's unlikely to start now.
When he steps in with jabs or his right straight, Kongo will almost lean back rather than hide behind his punching shoulder as he should. Furthermore, where punching effectiveness and elusiveness can be improved by combining a slip to the non-punching side with straight punches, Kongo comes in with his head in one place at all times.
With his head forever in the same position as he charges, Kongo's opponents could close their eyes (sadly not an uncommon feature in the heavyweight division), duck and throw back with a good chance of connecting.
When Kongo is punching he is so used to being at his range that he doesn't keep his guard up at all in many of his bouts. Watching him demolish some of the lower tier heavyweights whom the UFC matched him against in his early UFC career, Kongo will stand in front of them with his head upright, his non-punching hand down by his nipples and go completely unpunished for it.
Now that isn't to say that Kongo's hands are the worst in the UFC heavyweight division—not by any stretch of the imagination. Clearly his reach and power are massively effective against men who lack the ability to slip and counter. Kongo did an excellent job at landing his right straight in combinations against Mirko Cro Cop.
Cro Cop was actually a good matchup for Kongo stylistically. In Cro Cop's kickboxing career he had trouble with quick kickers who set up their strikes better than him, such as Ernesto Hoost and Andy Hug. Furthermore Cro Cop's money punch was not a slip and a counter (he rarely moved his head) but a side-step counter left straight.
By using his powerful kicks effectively against an opponent who was unlikely to take him down (on principal more than anything), Kongo could keep Cro Cop standing in front of him for his long straight punches.
Kongo's problems come against men who will make him miss and throw looping punches over his own. Hunt let Kongo chase him and caught him with a left hook as Kongo recovered his right straight. Pat Barry meanwhile used his lead hand to hook over the top of Kongo's jab.
Roy Nelson is certainly the type of puncher who could come over the top of an ill advised Kongo punch and starch the Frenchman, he also has the kind of ground game which should put Kongo off of using his great kicks. What Nelson doesn't have, however, is a great wrestling game or cardio. This fight, like all heavyweight fights, will hinge wildly around who fades first and whether the big puncher can land before he fades.
What is certain, however, is that Kongo's striking when we consider the whole—kicking, boxing and clinch work—is far short of great in just one major area.