Ricco Harbor can be really confusing - it's a boatyard with your initial dock area, another dock area you have to climb or sewer to get to, and a ton of grids out over the water.

You're learning about climbing here. Jump on fences to climb them, and use B to flip a gate when you're clinging onto it. If you press B when you're on the opposite side of a fence as a monster, you'll knock it off and into the water!

Go into the first cage. Jump up and flip the gate in the ceiling. Go to the first swinging thing, then the green arrow, then orange arrow. Now jump onto th eother swingy thing, and you're by a grey arrow.

Shoot the white spinner to raise the submarine. Jump across it then shoot the 3 mushroom guys to make little landing pads. Jump across them and onto the lifty thing (on its way UP) to get to the town area.

Now head right. You'll see a box with a tentacle. Grab it with B and pull it backwards to initiate the battle. During the battle, grab each arm and pull it off!! Yikes. Then wash his face off and pull the cork out of it. On to round 2. Pull all of his arms out again. Now grab his mouth and pull!!

The shine comes down right in the center.

Super Mario Sunshine Walkthrough