This is the walkthrough for Destiny Islands as it is featured in the Final Mix version of Kingdom Hearts. Sora and his friends Riku and Kairi decided to build a raft to try and visit the outer world, leading to them collecting materials and provisions for their journey.
After the cutscenes you can go and talk to Kairi, who needs a couple of items for the raft. The first log can be found on the beach nearby, and the second on the small island where Riku is. The cloth is inside the Tree House at the center of the island, which can be reached by traversing the wooden walkway. The rope is opposite of the Tree House, and can be found nearby Tidus, after climbing the ladder to reach his look-out platform. If you wish to save, you can enter the Seaside Shack on the beach to find a save point. If you return to Kairi you will receive a Hi-Potion, or a Potion if you talked to her for hints, or nothing at all if you said you were clueless.
But, before returning them to Kairi, you can engage in a series of duels against Selphie, Tidus, Wakka, and Riku, for some extra experience and Potions, and no downsides, as you can simply try again when you lose and still stand to gain some experience through Tech Points. You can also reach level six with a little effort here, at which point you will gain a useful ability that enhances your combat (only in the Final Mix version). Make sure to equip it in the ability menu if you need help during the fights.
Also note that the combat in Kingdom Hearts is at first rather sluggish. Sora's standard three-hit combo is slow, and it is easy to get 'stuck' in an animation or combo when an enemy is about to use an attack you cannot avoid due to the combo, or deflect at all. The aerial combo (jump slightly, then attack) is much faster, but somewhat harder to execute successfully.
Selphie is the easiest and can be found on the pier. She relies on her jumping rope for attacks with a decent range. If you time a parry (by hitting her weapon) correctly you will earn a Tech Point, and another when it lands on her head, which also temporarily stuns her. She is otherwise easily defeated as she prefers to try and jump back, then attack using her jumping rope as a whip or a flail, both of which are circumvented by continuously attacking.
Wakka can be found near Selphie on the beach, and relies on ranged attacks using his blitzball, but can also perform a very close range move if you attack him for too long. He has three types of ranged attacks, the first of which is a basic throw, the second he only uses when you are close to him, but not close enough to hit with a melee. He will step back a bit, then spin around and throw the ball. If you were about to hit him the backstep ensures you misses, and the spin prior to the throw will likely ensure you cannot deflect it back in time. Lastly, beware of his strongest move when he stretches, then shouts "Take this!", jumps into the air, and throws a much faster and stronger blitzball.
When attacking, either focus on deflecting his blitzballs (a good way to earn Tech Points, 1 point for a normal attack, 2 for the strong one) until one hits and stuns him, letting you attack him freely. Note that while stunned Wakka is one of the few enemies that can still attack, but he will only throw very slow balls in a high parabolic arc. Alternatively you can dodge all of his attacks by moving sideways, and getting in combos when you are close enough. Ideally you hit him as he is about to attack, as he will be staggered. When he is not attacking he will almost always counter with his melee, which you cannot parry.
Tidus can be found on the outlook platform and relies on his agility and close range attacks with a stick. He will often rush in and perform quick strikes, attempt to flank you and then attack, as well as leap backwards and immediately follow it up with a forwards lunge. Although he hits hard and will tend to make you miss, he is primarily effective if you keep chasing and attacking him. Instead, use your own mobility to evade his attacks, then counter quickly. If he dodges backwards, move sideways to evade the lunging strike, then step back in to hit him. If you continuously avoid him he will also stop and taunt you for a second, which can be useful to quickly hit him. As he uses a melee weapon his attacks can be deflected, but they do not always grant a Tech Point.
Selphie, Tidus, and Wakka
After defeating each individually you can talk to Tidus to fight them all at once. Selphie and Tidus will often cover for one another by trying to attack you in the back while you focus on the other. Meanwhile you must also keep your camera aimed at Wakka to be sure to dodge or deflect his blitzballs, ideally stunning someone so they are out of the fight for a few seconds. Alternatively you can also somewhat predict Wakka's strongest move (when he has not used it in a while), and ensure you will have ample space to dodge it, as you might not have enough time to do so when he telegraphs it.
Focus on taking down either Selphie or Tidus first, dodging the other while you do so. Although Selphie is the weakest, she won't pose as much of a threat unlike Tidus. Winning earns you a Potion, which can be repeated. Due to the partial random factor of fighting three very different enemies at the same time this fight is possibly harder than fighting Riku.
Riku will be the most dangerous single opponent, with a lot of HP, speed, and power. He relies on high jumps, sidesteps, and backsteps to try and either flank or dodge you, while while performing both swinging and thrusting strikes with his sword that have quite a bit of range. One notable attack is a strike with his sword, which is only used when you hit him two or three times while his guard is up. His most dangerous move is used when he is pushed onto his back, after which he will launch himself forwards, dealing a lot of damage if you did not sidestep him. He will sometimes let himself be knocked down on the first hit of your combo, after which you will take guaranteed damage if you keep going when he retaliates. As such, always be on your guard and ready to stop attacking at any time.
Riku prefers to keep some distance between the two of you, as he is faster and has more range. Try and flank him, then get in close and attack, preferably after already evading one of his own due to the flanking maneuvers. While attacking he will sometimes counter, but this often results in a parry. After his defeat you will earn another Potion.
This time you will need to gather provisions for the raft, the specifics of which you can get from Kairi by talking to her on the other side of the island (through the door she blocked yesterday). But first, talk to Riku on the way to Kairi, who will ask you about the raft's name, leading to a race minigame.
Sora and Riku will race for who gets to decide what to name the raft, which is otherwise inconsequential. The course involves crossing the wooden bridge, one part of which is unstable and collapses if you touch it, climbing the tower or making your way around it, then getting across the second area of the beach to touch the star tree at the end. Riku will attempt to use the zipline on the watchtower unless you block him on the ladder. Either way the zipline is faster, but only if you then use the treetops to jump to the objective instead of taking the long (and safer) way around like Riku. Be aware that Sora's jumping is slow and awkward, and rather imprecise for actual platforming. You will probably have to use the trees on your way back or else Riku wins. If he does you will be able to retry, but the ship name stays unchanged. If you win you also receive a Pretty Stone, which can be sold later on, and if you want you can keep racing him for more stones as long as you win.
Afterwards, head to Kairi who is at the raft to see what you need to collect. To start with, the two coconuts are gained by smashing the palm trees near the raft. Ignore the brown ones, and instead keep hitting them until you have collected two yellow coconuts. Next, the first mushroom can also be found nearby, in a small cave blocked by a large boulder which you can push away. The second can be found amongst the bushes next to the tall tower on the platform. You can also lift the nearby crate and drop it next to the cliff wall to reach a cave high up for a treasure chest with a Protect Chain, which grants a small Defense boost.
The drinking water can be collected (using the empty bottle from Kairi) from either the small spring underneath the nearby wooden bridge, or the larger pool back on the other side of the island. You can also collect the third mushroom from the Secret Place here, a cave hidden between the large tree and the pool (ignore the door and head back outside after the cutscene). The three fish are located in the sea, right at the beach, and can be caught by toughing them through running or swimming. The seagull egg is located on-top of a thick palm tree at the bridge leading to the island, climb the smaller one next to it to jump on-top and grab the egg.
When finally done, either fight with the kids again, or talk to Kairi to end it for today, receiving another Hi-Potion if you did not ask her for hints.
After the cutscene and the return to the beach area Shadows will constantly spawn in your vicinity, but your Wooden Sword is unable to hurt them. Head for Riku on his island, only for him to leave and Sora to end up with a Keyblade; the Kingdom Key. It will be more than sufficient against the Shadows, as such eliminating many of them while on the island is recommended for some extra EXP, as you can use any dropped HP orbs to restore your own Hit Points. When done, enter the Secret Place, by going through the door that has appeared in front of the cave entrance.
After reaching the small interior room at the end you will go through a cutscene, followed by a bossfight against another Darkside.
It will use the exact same moves as before, with a slightly higher defense and strength. Aim to hit the head when it uses the first attack when it summons a few Shadows, afterwards watch out for its homing projectiles when it goes down onto its knees. Its third attack will be new, and is used when it plunges its left arm into the ground, leaving its head entirely open to attack, up until the arm comes back out, holding a large orb. You can keep hitting the hands while it is holding it, but it will damage you if you touch it. It will eventually rise up and release it into the sky, at which point orbs of energy will periodically come down nearby and on-top of Sora's position. These are otherwise easy to dodge as long as you keep moving, but can also be hit away. Regardless you have to deal with them while it repeats the other two moves.