"Great King of Evil" Ganondorf appears as the final boss in The Legend of Zelda: Ocarina of Time, and you must face and defeat him in order to beat the game. This is no easy task. If you haven't already given it your best shot - remember, try every item in your inventory - then go away and do that now. You will get infinitely greater satisfaction from beating him unaided that you'll get by reading this guide. But if you're completely stuck, I guess I can't stop you reading ahead.
When you first enter the room there is a lengthy cut-scene which I don't intend to spoil for you here. However I will tell you one thing, which is that your fairy, Navi, will be unavailable to help you. In other words, no fighting tips and no Z-targeting. When you do attack him, you'll be aiming manually.
Preparation: get Biggoron's Sword if you can, as many bottles as you can find, and fill them all with red fairies, which can be obtained in large quantities by playing Zelda's Lullaby by any Gossip Stone. (There are four Gossip Stones within easy reach of the final arena, just outside the Temple of Time.) Visit the Fairy Fountain immediately outside Ganon's Castle (you'll need the Gold Gauntlets) for a power-up which will halve the damage you take for each hit during the fight. Don't open any of the pots in the preceding room: you'll need these.
The room you enter after climbing the immense spiral staircase is directly over the darkened, metal-clad room you just left. The top room is where all the action takes place, but both of these rooms form part of the boss arena. The central column in that last room supports a concrete square platform in this one. In the four corners of the arena are smaller square platforms which are stable. The rest of the floor is made of large tiles which Ganondorf can destroy if you step in the wrong place. Then you'll be in danger of falling through holes and plummeting all the way to the distant floor, which will do you damage. You'll then have to climb all the way up the side of the central pillar to get back to the scene of the action. I'll explain how and when Ganondorf destroys ground later, just bear in mind that the central pillar and the four corners are the only patches of ground that are guaranteed to remain for the whole battle. Also, there are pots in the lower room containing copious amounts of power-ups. If you were careful, you should've left these undamaged when you passed through earlier - you may well need them later.
The stairs are now locked at the top and bottom, by the way.
Ganondorf's first action as the fight begins is to hammer his fist downwards into the ground. This will cause the first ring of collapsible tiles around the central platform to collapse. It will also send out a shockwave from the centre. To avoid this you should go straight for one of the corners of the room and stand on the safe platform facing Ganondorf. Centre the camera behind you manually by pressing Z, so you can see what he's doing.
Ganondorf's attack pattern
He will float and waft in the air above the centre of the platform - he never moves from this position. Periodically he will raise a hand in the air and gather together a sparkling ball of energy, which he then hurls in your direction. When it hits, this can do a lot of damage - about three full hearts out of your maximum of twenty, or six if you haven't got the half damage power-up - and knock you backwards. These are easy to sidestep or will disperse if they hit your Mirror Shield.
After you've damaged him a bit (I'll tell you how in a sec), he will start to occasionally use a second attack. This one starts with gathering a ball of energy but instead of being bright yellow, this one will be black. It will also take a lot more time to gather. When released it will fire not one but FIVE identical fireballs at you from all directions, all of which are as dangerous as a single one (although only one will do you damage - there's a short period of immunity after being hurt). These are much harder to dodge.
His other attack only occurs when you are foolish enough to jump to the central platform underneath him. If you do this he will punch downwards again, just like at the start, creating an identical shockwave and removing three randomly-selected tiles from the playing field. If you get caught in the shockwave you will almost certainly get hurled into oblivion and fall to the bottom of the lower room. This will cause damage. Also, since there's no option but to climb back up, you will have to visit the central platform briefly when you get to the top, meaning another punch is certain. So when you do get there, run away fast.
Your strategy
Like all bosses in "Zelda 64", he must be stunned before he can be damaged. However, unlike the rest he kinda has to be stunned twice. If you try any projectile weapon on him while he hovers in mid-air, he will simply hide behind his cloak and deflect it. Instead, you need to play a game of tennis with him, almost exactly like the one you played with Phantom Ganon in the Forest Temple.
Just as a fireball is coming towards you from Ganondorf, and just half a second before it hits, you need to slash your sword. This will deflect the fireball back at Ganondorf. The timing on this is difficult to get right at first, but when you suss it you can do it quite consistently. (Use Biggoron's Sword if you have it: the reach of the swipe is twice as long and this makes the deflection timing easier.) Ganondorf's pretty good at tennis - better than Phantom Ganon, anyway - so it's pretty likely he'll deflect it back at you several times, sometimes as many as seven. Keep your nerve and keep the rhythm and eventually he will slip, and absorb the energy.
If Ganon starts to gather a big black ball attack, the tennis technique will not work. Instead, you should in turn start charging up your sword for a spin attack. Wait for the right moment just as all five balls are converging, then release B to deflect all five of them back towards Ganondorf. This will instantly stun him in the same way.
Now stunned, Ganondorf will huddle while hovering. You still can't reach him with your sword. However, you can try your projectile weapons now. Normal, Ice or Fire Arrows won't do any good, but your recently-received Light Arrows will. Pull out your bow with Light Arrows equipped and quickly (manually) get Ganondorf in your sights while you pull back an arrow, then fire. Try not to miss: a Light Arrow costs a respectable quantity of magic. Also, try to make this quick, because if you take too long aiming, Ganondorf will recover and resume his attacks.
When the Light Arrow hits, Ganondorf will suffer a nasty yellow explosion and drop to the ground in the centre of the central platform, now stunned and vulnerable to proper attack. Pull out your biggest sword and quickly jump over to him. (DO NOT attempt to jump straight from the corner, the distance is too far.) If many of the tiles are missing, the jump might be too long for you, in which case slip on your Hover Boots for a moment and do a rolling attack off the edge of your tile, which should take you far enough. Slash him once or twice, then quickly hurry back to your corner before he regains his power and ascends again. It's best to try to perform a jumping attack as this doubles the damage dealt by your sword. However, anything will do. If you can spare the arrows, you can actually even shoot him with a normal arrow from afar - this means you don't even have to move, but the battle will be longer. Make sure to use plain arrows so you don't waste magic - Ice and Fire won't do anything for you here.
As an aside, it is said that if you repeatedly perform the quick spin sword attack (swirl the joystick and stab B), it is possible to continue to damage Ganondorf without ever giving him time to get up. I'm not sure how much truth there is in this since I never mastered that particular technique, but if you have had success with this or can provide more information I'd be interested to hear it.
If you find yourself short of arrows, health or magic, you should drop (carefully) to the floor below. (Note! If you find yourself falling through midair, and you're next to a ladder, you can grab the ladder and save yourself from being hurt by the fall. This works on the side of the central column, so if you're careful, you can jump towards it, fall a while, then hit A to climb down.) You can collect as much as necessary from the pots, then climb back up to face Ganondorf again. If you have red fairies then you needn't worry about health, at least, since a red fairy will restore all your health. (Do not use a red fairy, ever. Wait until you're dead, to get the most out of it.) Continue to repeat your attack pattern and eventually you will wear down Ganondorf's defences until he dies. Now witness the spectacular end sequence and the the final part of the game... ;)
This was the tenth boss from The Legend of Zelda: Ocarina of Time.
Previous boss: Twinrova.
Next boss: Ganon.