Horsehead is a relatively simple boss; your target is his exposed head, and a simple jump attack will hit his weakpoint for massive damage. He carries a weighty mace, so be prepared to evade his crushing swings.
Again, this boss’ weakpoint his his head, which you need to literally decapitate twice before you inflict any damage. Both times, the decapitated head will fly around the room shooting fireballs, so you need to despatch his third head as swiftly as possible. You can defend yourself against the torrent of fire by using the shield spell.
To defeat Iron Knuckle, you must first dismount him from his horse. He moves from side to side, and you must jump over him and thrust your sword down into his head a few times. After that, he’ll become vulnerable - you must block his sword attacks and counter as with regular Iron Knuckles.
Carock will shoot magic at you, and is impervious to your sword attacks. The trick is to cast Reflect and stand in the corner, which will repel some of his attacks back at him.
Gooma is built like a tank, and hits like one too. He carries a spiked ball and chain, which he throws at you from a distance. Your only chance to survive is to make your time - evade, run in, attack, and run back out again! A downwards thrust is the only way over him if you get trapped.
Barba’s only weakpoint is his head, so you need to attack him has he emerges from the lava. By standing on the middle platform, you can reach any lava pit quickly. He’ll attack, so your best chance of survival comes with efficient use of the shield spell.
Thunderbird uses a shield which you must first remove with, counter-intuitively, a thunder spell. Casting a shield spell will help protect you when you attack his now-exposed face with a jump slash. His offensive consists only of fireballs, which can be dodged or reflected.
Your evil shadow can be dispatched easily by running to the left side of the screen and fighting Dark Link with your back to the wall. By attacking furiously, Dark Link won’t get a hit in, and will spend his time jumping at you in a futile attempt to inflict damage.