General tips and short individual guides for each boss. I might release a more in depth guide at some point, as well as one for the other difficulties.

General Stuff:

• You HAVE to use Ganondorf to get even decent times. His up smash obliterates bosses and can hit even floating bosses, unlike Peach's down smash.
• You can buffer inputs at the beginning of a boss fight. So while the screen is black and the fight is loading, if you are holding right for example, you will start the fight dashing to the right (not walking).
• The order is always random, except for Tabuu, who is always 10th out of 10.
• Bosses 7 through 9 generally move faster than if they appeared earlier, as well as having very slightly more hp. This makes certain bosses tighter execution, and some you just don't want to see later on at all cause the optimal strats won't work. Crazy Hand and Galleom are the only two who I would reset on if they appear later, but if you aren't going for WR time, it's fine.
• This run is RNG heavy. If you don't like RNG killing your runs, this isn't the category for you.
• Use Ftilt or Jab if the boss is very low on HP. Since they're a little faster than up smash, you should use the fastest move available if it'll kill.
• Side B, even though it's just a command grab, does have a hitbox that hurts bosses. Usually you won't use it, but it's good to know all your options.
• Dacus. If you don't know how to Dacus, you should learn how to do so before going for good times in this category. It stands for dash attack cancel up smash, and will let you slide to the bosses quickly while doing an up smash. The easiest way to do this is to dash attack with the C Stick, and up smash with A + Up during the first two frames of your dash attack. This will take practice.
• For the best times, you should buffer a dash right so you can prepare to Dacus for the very first fight. Since you don't know which boss it'll be, and this is how most of them start out, this is the input you should buffer. Waiting and reacting is also an option, but you'll lose precious time, and will be more restricted to tight execution.
• Yes, you're spamming up smashes at some points, but remember to have as little time between the up smashes as possible. The more frames you can save, the better.
• The portrait in the background before you fight the next boss, is the next boss you're going to fight. Learn the differences between bosses like Meta Ridley and Ridley, and Crazy/Master Hand.

Without further ado, boss specific stuff!

• Master Hand - Dacus --> Another up smash --> Up air will kill him. If you only hit with 3/4 hits of up smash, any aerial or up b in addition to this will finish him off. You may have to delay your dacus a bit - you're aiming for his middle-back area, so that every up smash hit connects. You can finish this in under a second (IGT) if done correctly.

• Ridley - Ridley kills more runs than anyone. Just start out with Dacus, and up smash him until he dies. You may have to up air or something to finish him if he moves around right before he would normally die. If he gets the chance to do anything, it's hard to stop him, and you'll lose a lot of time. Most RNG dependent fight in the game.

• Petey Piranha - If you space your up smashes correctly, you can up smash him just twice and he'll die. You're aiming for the left cage, his left arm, and his head all at once. Pretty difficult to space. If you miss this, just keep on up smashing the left cage till he dies. You only have to kill one cage to beat him, and you start out closer to the right one. You can finish this in under a second (IGT) if done correctly.

• Crazy Hand - Dacus (to the left) --> Up Smash --> Up Air. This is a little more difficult than Master Hand, both in spacing and how fast you have to do the up smashes. If he appears 7th through 9th, this strat doesn't work. The best backup I've found is to turn around for the second up smash, cause he'll usually turn into a fist right there for his next move, but this is unreliable. Usually I end up resetting if he appears this late.

• Galleom - Dacus --> Up smash till he dies. He has lower HP than other bosses, so he dies pretty quickly. This one is pretty tight execution though. It's also worth noting his moves have a deceptively long startup for the most part, so keep on up smashing him if he starts doing something, don't be scared. If he appears 7th - 9th, it becomes a lot more difficult and will often cause resets, but your overall gameplan is the same. You can finish this in under a second (IGT) if it goes perfectly.

• Meta Ridley - You actually start out in the air a little bit, so the best thing to do is to buffer a fast fall (hold down at the start) and up smash as soon as you land. It might take a little bit of practice, but both hits will hit if you do it properly, and any up smashes you can get in this fight are really valuable. Most of the time, he'll be fading to the left a little when you first up smash him. This is pretty hard to do, but you can up air towards him --> fast fall --> up smash his feet right when you land. You'll wanna stay on that side of the ship for a while, up smash him when he comes back. If he's very low on hp and offscreen, wait a tiny bit and then jump offstage at him and up b to kill him. This is the most tight execution fight, so it will probably be hard at first - one of the lightest RNG fights though, on the bright side.

• Porky - Porky is really annoying. He can start out with 3 moves. The slow walk with a hitbox, the run with a long startup, or the multihit poke thing. Ideally, he does the run with a long startup, cause you can just dacus at him and up smash him till he dies. Unfortunately, this only has like a 10% chance of him doing this, so it's really unreliable. The best thing to do is Dacus, then dash into him and roll behind him. This is kind of hard to do, but it avoids the poke move, which is a huge pain and he usually opens up with it (even if he delays it). If you get behind him like this, up smash him till he dies. If he does the slow walk, you probably should just reset. If you really wanna keep the run though, the best thing to do is to stand close to him, crouch cancel his walk hitbox, up smash instantly, hold down right when your up smash is ending, repeat. You'll up smash a little slower, but this is the quickest, most consistent way of finishing him off. If you up smash too late or don't crouch cancel, you'll be knocked down though. So make sure to up smash right when you crouch cancel his attack.

• Duon - Open up with a dacus. He'll use a move. You'll have to learn the timings of each of his moves, the startup of the animations and stuff. If he does his spinning move, just roll back. Any other move, spotdodge it (or roll if you wanna play it safe). Powershielding is optimal though if you get to that point. After that move, just up smash him until he dies. If he jumps, you've probably taken too long and should reset.

• Rayquaza - Open up with a dacus. Up smash him till he dies. He'll usually be able to get a move off - just crouch cancel it and keep on up smashing him. If you crouch cancel while at higher percents, you may have to dacus into him a second time so that your up smashes still hit. If you're for some reason at way too high of a percent to crouch cancel his attacks, just jump over him instead or amsah tech into him. Usually you shouldn't be at that percent though, even if he appears 9th.

• Tabuu - Dacus --> Up Smash --> Up Smash. Three up smashes and he's dead. He has 3 opening options: Teleport instantly, teleport instantly with explosions, or just sit there and do nothing. Luckily, sitting there and doing nothing is his most likely option. If he does anything else, he's totally unpredictable and difficult to hit, so you should reset unless you're wayyy ahead of your PB.