This is basically a breather level, nothing in it is particularly hard, even in 100%. There are a lot of minor obstacles that can waste your time, but nothing run-ending. Messing up the heart grab and dying is the only real danger in the whole stage. The general movement through the stage is the same in any% and 100% waterless route, and waterful route has a different cave, but generally everything done in any% is also done in 100%.
Getting past the lumberjacks is pretty simple, you can just break one of the blocks with a mid-charge and a dash shot, or use tornado. Either way, you want to break a block and dash jump over the other. If you jump from far enough away you can get over the other with little to no delay.
Before getting to the cave, charge a mid-charge shot and fire it near the ceiling, this will destroy any blocks that try to fall on you until the first boulder guy. Generally, you just dash jump in front of the boulder guy as it's falling and wait until it gets below you before continuing to the right. There's a different way you can get around the first one that saves a few frames, instead of landing on the lower platform and jumping over it from there, land on the high platform the boulder guy lands on, then dash jump left to avoid taking a hit and loop back around him.
The rest of the stage there's very little to slow you down. There are a handful of enemies, but most of them die to 1 dash shot. The guys that jump into the mech suit die to two uncharged shots, or a mid-charge and uncharged shot, so just kill the enemies in your way, don't sink far enough into the mud to slow you down, and keep dashing to the right.
Chameleon fight Edit
You can open the fight one of two ways, either fire a boomerang immediately, or go to the left wall, wallkick once, turn, and fire a boomerang. You can fire a boomerang first as a backup, but it shouldn't be necessary. Climbing the wall right away is faster since you fire the boomerang directly into Chameleon rather than waiting for the boomerang to loop around first. If you go for the off-the-wall shot, do a dash wallkick off the same wall and chase Chameleon to the right and hit him for the second time.
After the opening shot(s), get to the center. There's a simple visual cue you can use for when to fire the next shot. When Chameleon gets hit, he rocks his head back as he recoils, when his head is all the way back, that's when you fire the next boomerang, it should hit him with minimal vulnerability frames.
100% differences Edit
Open the stage the same way as in any%, except when you reach the cave, climb up top and swap to boomerang. The miniboss has half a second of invincibility after hits, so don't spam any shots against him, it won't help. Use 18 boomerangs and switch to buster and use dash shots to finish him off. Be careful how you shoot him, his claws tank your shots. If he jumps you can shoot him in the feet, otherwise jump and shoot the head.
Waterful route Edit
After the miniboss, drop down into the pit. Break two of the lower blocks, leaving one or two bricks at the bottom. Stand on the bricks you left at the bottom and dash jump to the right. When you reach the third black band out from the platform (the ledge the heart's on should be in vision) fire a boomerang, then let yourself fall a ways before going back to the left. Charge up as well, and once the boomerang returns with the heart, swap to rolling shield and use a charged shield.
With charged rolling shield, you can get through the first boulder guy without having to stop in front of him, you either want to jump up and through it, or land on his ledge and dash underneath. You get 12 frames of invincibility once the shield breaks, so you just need to get away from the boulder guy in that time. Charge up again and use another charged rolling shield on another boulder guy when you get the chance.
Waterless route Edit
After coming out of the capsule, charge up and swap to ice and drop down the pit to do waterless. The easiest way to do it is to break the top 3 blocks, then fire the ice sled from a standing position very far to the left, facing to the right. This will give enough space for the sled to pick up some speed before dropping. Don't jump too early or you'll bonk your head and just fall, but jumping too late you won't reach. The sweet spot isn't too small though, so with a bit of practice you should be able to reliably reach.
A faster way to do waterless is to break a lower block, fire the sled as you move upward, then break the top-most two bricks with a doublekick. The sled can fix itself in place halfway into the third block, stand on the edge of it. Then jump over as usual. You can also swap to boomerang after the sled drops off screen and fire a boomerang and then just wallkick and go back to the left instead of climbing the ledge.
Cf-0 Chameleon Edit
If you pick up a small ammo container in waterless route, 3 small containers in waterful route, or one large in either route, you can do the cf-0 Chameleon strat. After the last mech suit guy, start holding a charge so you can enter the fight fully charged. Release the charge to start the fight, then at some point during the fight, fire a boomerang to hit Chameleon, then jump and fire a boomerang to get it to curve down and hold charge. Drag the boomerang over to where Chameleon is going to go and get it to hit him, then chase Chameleon to the other side again, get to the wall, and release the full charged boomerang. You want to release it against the wall for a few reasons. First, it will hit chameleon very quickly, and second, one of the pieces will despawn offscreen immediately, which will allow you to fire a boomerang again without having to wait. Unless you wait until the final hit to set up the cf-0 shot, you want to be able to fire boomerangs soon after, so you need to get at least 2 of the charged boomerangs to despawn.