Starting in the entry of Area 5, head to the right using the entryway. It's blocked off by a grate, in which Agent 3 can simply clip through it in Squid form. There is a Propeller-Lift. Use it and get up the wall it stops at. Now, get up the grate slope. There is a wall behind the Inkrail, but it's not the core of the Inkrail. Using the wall, there are two dry sponges. Use the sponges, and get up the small wall. There is an Inkrail next to Spongy Observatory, use the Inkrail and use the grate path, get to the next cube platform and get on the wall, expand the sponge and get on the Propeller-Lift. There is another Inkrail, but once active, it can be used as an elevator. There is another Propeller-Lift in the distance, where using a Hero Shot or a Burst Bomb will have the platform head toward where Agent 3 is located. The kettle for Far-Flung Flooders isn't on the highest peak of the area, it's the platform halfway across where the Propeller-Lift is about to go back to.
You start on a platform with some Power Eggs. Get them and super jump on the launchpad. You are in a separate area now. There is an area with two Flooders. If you go to the right, there is a key but a Twintacle Octodiver will appear and you have to splat it before you get the key. In front of the key is a Vault. You can unlock it, revealing a launchpad. It will launch you to the top.
Checkpoints 1 and 2
You will have to go on top of the Flooders and on more platforms. On top of both Flooders are Twintacle Octotroopers. Splat them, then you can safely jump around. Get some Power Eggs lying around on some decorations. On the longest platform, there is some Armor in a crate, so get that. Now, go on the platform with the launchpad but don't activate the launchpad. Instead, go to the back of the platform and look down. There is another platform with a launchpad. This will lead to the Sunken Scroll area.
You will land on a platform. There are two Flooders going around in a small square. There is a gap, and in the middle there is a crate with the scroll. There are also some Balloons. The Flooders have Gushers on their heads. Try to jump, and get the Sunken Scroll. Then, ink up the other platform, leading to some Power Eggs and a launchpad.
This checkpoint starts with a Vault. There is a maze with six Flooders. Go to the left, make one turn, and go all the way down the path to get the key. This may be hard because the Flooders may come around the corners. Go back to the Vault which will unlock a Gusher—You will have to ride the Gusher and jump onto the closest platform.
On top of the Flooders there are three Octotroopers, and one Octosniper. Jump from platform to platform to splat the Octarians. Some Power Eggs are on some decorations. On top of two Flooders with crates, there is Armor in the crates. Also, there will be some Balloons. When you splat the Octosniper, the key will appear on the Flooder. Go on the platform under the old, turned off Flooder—There are some Power Eggs here as well. Then, use the launchpad. Use a Seeker to go to the Zapfish. Mission Complete!