Giga Aspis (Intro stage boss)

Fire super-shots at the head. It will move off the screen, then slam its tail from the same edge where it disappeared. Stand on the opposite side of the screen and jump the rocks that get kicked up, or I believe you can super-shot them away. After doing this, the snake will move back on the screen low to the ground before straightening up again. Sometimes the snake dives toward you, goes off the screen, then comes on that side again. This then reverses all of its attacks.

Rayfly (Locate Giro boss)

A plane. It keeps dropping blocks that shoot at you. Destroy the blocks by shooting the ones with red gems and the resulting explosion will damage the boss if the plane is above the blocks at the time.

Tentalamia (Mini-boss)

This is what looks like a large dive helmet sitting in the center of the room with an eye or eyes in the middle. Stand on top of the machine, in the center, and attack the snake-like things that come out. When you have hit enough of them, the mini-boss should blow up.

Crushpactor (Mini-boss)

A tank with a spiked arm. Some variations of this boss have a scrolling floor which will pull you toward the tank. This is bad; if you get too close, it'll slam its arm down on you, and once hit, it can be hard to escape at times. So in these cases, stay on the wall and fire from there. When the tank charges you, if it has its arm up, you need to stand below it, in the corner of the room. Otherwise, you have to climb the wall, although the tank will knock you off the wall when it slams into it if you are touching it at that moment. The tank can also fire a laser, though if you damage the cannon enough, you will destroy it, and it can no longer fire.

Powmettaur (Mini-boss)

A giant Met found in Area H. Just blast the heck out of it whenever its helmet is up and its eyes are revealed. When it hovers back and forth, you need to dash underneath it to avoid taking damage. The Mettaur will toss out helper robots that you have to destroy separately, but you'll probably end up hitting them while you're shooting at the Met anyway.

Lava Demon (Mini-boss)

This is a normal Galleon that gets engulfed in lava and turns into a monster. You can't hurt it in its lava form; wait until it goes down to just a head sitting on the floor, and aim for that. Thunder ball attacks from Model HX (level one charge) work pretty well.

Diadrake (and variations) (Mini-boss)

These things can send out sonic beams that reflect on the other side of the screen. Just let them go over your head and don't stand too close to the far side of the screen, because you need to be ready for them to rebound. When it air-dashes toward you by starting high, run forward and stand underneath it to avoid it. When it dashes by starting low, run away from it and stand in the opposite corner of the room. You can slash off the lion's tail, thereby forcing it to spend time making a new one.

Pandora

She's a witch archetype. She can fly around on her staff and create a potion-like thing which will move toward you and shatter (climb the wall over it). She can also send balls of lightning after you. When she sends the two pieces off her head after you, whack them repeatedly to get them to retreat.

She disappears and reappears a lot. To finish her off quickly, cast a tornado on top of her right after she reappears.

Prometheus

He, too, can teleport, and he disappears and reappears before just about every attack. When he appears in the center of the screen, in the air, he'll cast four skull pods to the corners of the room which shoot purple shots at you. You can destroy the pods (though they have a lot of hit points each), or keep moving from one wall, then down and across the room to the other wall, to try to avoid the shots. You can still hit and damage Prometheus in the center of the room while doing this; I would try to strike him with a charged shot with every pass that you make.

When Prometheus appears on the ground in the center of the room, he's going to send rainbow blades down the wall, across the floor, and up the other wall. Dash-jump off the wall and over his head to avoid this (hit him with a charged attack first).

Finally, when he appears on one side of the room, he's going to do a series of slashes that usually ends with a corkscrew uppercut that carries him off the top of the screen, though sometimes he'll just slash. You can avoid this attack by hanging out on the wall in the upper corner of the side of the room that he is heading toward; his final slash and his corkscrew will just barely miss you up there.

Drop a tornado on him in either of his first two attacks (where he stays in the center of the room) to wipe him out pretty quickly.

Prometheus and Pandora (Area O)

Each one appears, performs an attack, then disappears, alternating between the two of them. Damaging either one will take health off their shared energy meter. Most of their attack patterns are the same but there are no walls here to climb, which makes it difficult to avoid certain attacks. The easiest thing to do is just plant a tornado on top of them whenever they are motionless (such as when Prometheus is doing his thing in the center of the screen). (Side note: Does anyone but me find the Highlander plot to be a little...well, ridiculous?)

Omega (Area N) See Model Ox Guide for More Details

He's very fast and he has virtually every technique that Zero ever obtained throughout the entirety of the X series. Probably the easiest way to deal with this guy is to stay away from him, as most of his attacks require short range to use. Blast him with charged super-shots at every opportunity. If he does get close, hit him with a triple-slash if you can, but only if the first slash makes him reel; otherwise get the heck out of there. One thing you do not want him doing is popping his seven-hit combo on you, but he has to get close to do that, so don't give him the opportunity.

Serpent (Final boss 1)

He fights a lot like a Street Fighter character, which is kind of cute. And he can use OIS mode, which is even cuter. But he's relatively slow (at least compared to Omega); this helps you to keep away from him and to dodge his attacks. His cannon shoots a {- shaped group of tiny spheres at once that move at slightly different speeds from each other. He can shoot horizontally or diagonally from the air. He also has a slide, an uppercut, and a ground-slam move. And he can charge up and fire a large sphere that moves slowly enough to make it nontrivial to jump over (but you can shoot it to slow it down and/or knock it off course). Stay at a distance and blast him. If you get good at dashing (and dash-jumping off walls), you shouldn't even need a Sub Tank.

Model W (Final boss 2)

He has several modes. When he's low to the ground, you want to hit his normal head. When he rises all the way up, you need to strike the green gem in the forehead of the big lower face. Plant a tornado in the center of the room in either case to hack off large chunks of his energy meter. If you run out of weapon energy, jump and slash (if you can - the clinging sparkles tend to get in the way here). If all else fails, try shooting straight up at the gem with Model FX.

His attacks are varied. He has green spheres that can break into daggers that travel diagonally. He can also grab you and drain health (mash the buttons to escape). At the middle level (where you can hit him practically anywhere), he'll start shining a purple light that shoves you away from it, as well as dropping little sparkles that will cling to you, slowing you down and making it near impossible to jump. He also has a fireball attack; after you dodge the large fireballs, jump and circle-slash away the little ones. And at the highest level, the hands on either side start shooting lots of shots from the right and the left. He can also form a crystal in the middle of the screen, which the hands then smash; stay at the edge of the screen and jump to avoid the shards, then dash under the hands as they return to their original locations.

Note: If you die to either of the last two bosses you have to fight them both again. You have no opportunity to refill your weapons or Sub Tanks, so only use them when you are fairly certain you have a shot at winning.

Credit for this guide goes to Megachu exe of our forums.