Aqua Star
100% Route
Note: this page was adapted from swordsmankirby's guide. Some strats may be outdated.
3-1
At the beginning of the level, headbutt (or jump over) enemies until you get fire (left). In the second room, float up instead of taking the Zebons, grabbing Shard 1 along the way (right). Though you can squeeze through the Scarfies, it's faster to stay left and fire over because the platform is lower.
Hold the Emp enemy in your mouth as you navigate to the right, combining with the Poppy Bros. at the end (left). There are few things to be careful about. If you're too close to the Emp, you can swallow the enemy behind it. The Gloms (frogs in the wall) will destroy anything in your mouth, so it is imperative that you jump quickly past them. A safer strat would just be to swallow and take out the powerup later. Finally, I like to spit the enemy out in between the two sets of collapsing platforms so that I don't lose running speed. For whatever reason, you go back to walking speed if you spit on those platforms, even before they fall down.
In the room afterwards (right), just jump and avoid enemies. The two floppers are in the way, so puff them out of the way. The waterfalls push you down, so account for that when jumping.
Drop below the miniboss and run into it with the snowman powerup. After the four hits, the platform will sink, revealing Shard 2. To get to the door when the Tick enemy on the right is still there, just float up and walk towards the exit. Depending on its movement, you might be able to just jump over it or freeze it incidentally during the actual fight, allowing you to reach the exit more directly.
Navigate towards the bottom of the room and break the block with the snowman powerup. When climbing down the platforms, I like to hug the left side, but some people prefer to go more towards the middle. Since the snowman attack lasts so long and there's nothing nearby to help you break the block, you should activate it as soon as possible (i.e. once you reach the lowest level) to minimize the waiting time. After getting shot up into Shard 3, remove the powerup while falling to avoid faceplanting and run it into the Zoos. To avoid the Kapars, just run over the blocks.
3-2
This is the first level with significant amounts of moving water. It came into play in 2-3, but very minorly.
As in the previous level, combine two powerups (stone and fire) without swallowing the first one. The difference here is that the two enemies are found in different rooms. Right before the Bobo, you can pass over the Emp with a few well-timed jumps.
The miniboss fight is straightforward with the volcano powerup. Conveniently, the first attack always shoots up, so use that to break the block. Collect Shard 1 after the fight and remove the powerup as you leave. Note that you can't remove a powerup in the next room.
In the river autoscroller, there are a few places where you can jump that save some time. The first place is where the Kany (crab) is, saving about a third of a second. In the middle of the autoscroller is a jump for Shard 2. Finally, jumping before the penultimate waterfall saves about half a second.
At the beginning of this next section, inhale for a short amount of time to avoid faceplanting. Then, swallow the Kany enemy, grab the invincibility candy, and just run forward. Shard 3 is at the bottom of a set of two waterfalls. Besides avoiding faceplanting with the enemy in your mouth (allowing you to just hold right), you can also spit at the enemy after your candy wears out.
Since the water is running to left, jump repeatedly up the slopes, headbutting Bouncys when convenient. When you get underneath the Bronto Burt before the Galbo, jump and inhale to grab fire while landing on the platform. Make your way to the second Galbo by alternating jumping and fire. Here, float up and single fire across to the platform near the top of the waterfall. Perhaps the most time-consuming mistake is hitting one of the Splinters (spiky logs). Usually, these logs hit multiple times, causing your recovery to take forever and possibly knocking out your fire powerup.
3-3
After single firing across the first room and into part of the second, put the Kapar enemy in your mouth. Note that if you're standing on the left half of the block, you'll swallow it with the enemy, causing you to fall in the water. Afterwards, jump over to the Blowfish in the water and combine for the ninja star powerup. I like to do one big jump and one small jump to get closer to the Blowfish, but far enough so he doesn't explode.
Take the water jet up to the entrance into the mountain at the top of the screen. While standing on the plank I like to turn around twice to make sure I still have my running speed. Instead of jumping twice, you'll sometimes be in a position to ledge grab, which I think is a little bit faster. Once inside, move to the left and use the powerup to get Shard 1. Like in 2-1, I like to slide into the wall to quickly change directions. Slide into the block and immediately take your powerup out. For some reason, it'll go into your mouth as you step on the trigger. After exiting, spit out the powerup, inhale the Cairn enemy, and walk into the cutscene trigger.
The next room is somewhat risky, because missing the powerup means restarting the level. With the Cairn enemy in your mouth, jump and spit it at the first Fishbone for the animal statues powerup. Float up and jump into the hole. The miniboss takes four hits, and since a large area around it collapses once it's killed, it's easy to get stuck in statue form while the floor collapses. The best real-time strat for killing this Kapar miniboss is to get one hit by bonking into it with the powerup, two hits by entering the powerup, and one hit by breaking out of it. Due to the invincibility frames, you have to delay the last hit a little bit. A safer strat involves going on the left side of the miniboss, where the floor doesn't collapse (right). Afterwards, grab Shard 2 and fall through.
The next shard is one of the more annoying RNG segments in the run. After breaking the block, you need to keep trying the powerup until you get Rick. To climb, hold left against the wall and press A at a certain rhythm (i.e. it's not mashing). After climbing to the top and collecting Shard 3, drop down and break out of the powerup to avoid faceplanting. My visual cue is to press B when Kirby lines up with the second wooden platform visible on the right.
Afterwards, go to the right and float up, using the collapsing platforms to jump off of. For some reason, the ones on the right collapse almost immediately, while the ones on the left take about a second to fall. Once you get past these platforms, float past the last enemy and fall towards the exit. Keep the powerup, because it's useful for the next level.
3-4
At the beginning of the level, use the animal statues powerup to sink through the water faster. It's nicest to get Pitch here because of its horizontal speed. Conversely, Kine sucks because you can't move, and I'm still not sure what the best way of dealing with that is. The remaining four friends are more or less equal, falling in between Pitch and Kine.
Throw away the powerup in the next room and inhale one of the Floppers. By holding the Flopper above your head, you can go through most of this room really quickly, but there are many obstacles in the way–go too high and one of the boulders will hit your fish, and go too low you run into a lot of enemies. The standard strat is to float up to the height shown in the top-left, allowing you to avoid everything. I like to go lower, as seen in the bottom-left, because I'm scared of the boulders. While you get to hold onto the Flopper longer at this height, you'll also run into one of the enemies (bottom-right). It is unclear which is faster.
In this room, the objective is to swim up without touching anything and grab Shard 1 at the top of the room. There are currents pushing you horizontally, with the top-most one flowing to the right. As a result, we need to stay towards the left side of the room. The clip on the left shows my preferred route, though it's possible to essentially hug the left side the whole time. In the beginning of the next room, there's a slope that you can slide off, saving a little bit of time.
Later on in the same room, you approach a pole with Shard 2 off to the bottom-right. You can slide down it quickly by simply double-tapping and holding down. Turning around on the pole can be done without losing any vertical speed. The quickest way is shown in the top-left, where you can inhale before getting to the bottom. Note that pressing A here doesn't work as well because it'll cause you to jump a little bit. The safer way involves just sliding to the bottom and running along the ground. Immediately after, inhale the Blowfish and proceed to the end of the room, swallowing only at the end. The enemy is swallowed here because going through the loading zone cancels a bit of the swallowing animation.
An easier Blowfish is one of the ones right before the pole (bottom-right), but swallowing it is really slow. Furthermore, pressing B on the pole needs to be done lower because the recovery animation with bomb (which causes you to rise a bit) takes longer.
The Blowfish miniboss has a quick-kill that involves getting stuck in the alcove (left). The clip shown here shows the riskiest way of doing it, where you start moving towards the exit after the second bomb. To stay up in the alcove, alternate between pressing A to swim up and B to throw a bomb. Make sure to only tap B, otherwise you'll hold the bomb up and it'll hit the ceiling. In the final room, stay close to the bottom, avoiding the random boulders and Gordos. In between the second set of Gordos is Shard 3 sitting in a pit.
If you lost bomb before the end of the level, you can quickly re-enter the stage to grab a Pedo (yes, that's its actual name) before heading to Acro.