Sometimes the best treasures are hidden in plain sight.

Giant clams won’t pass up a free lunch but they are very picky.

Bioluminescent plants bestow gifts to those who find their true brightness.

Curious eels love to hide alone but hiding together is always better.

Cave eels love guests that aren’t too bright.

Phytoplankton swarms will follow anything but where are they trying to go?

Cuttlepups seem to have no problems navigating the cave's hazards.

Cuttlepups enjoy following glow bulbs.

The Nautiloceros can destroy metal walls.

Sometimes when a lock is rusted shut the best course of action is to find something to break it.

The claw can pick up bombs.

The claw can grab and pull hatches.

The sub’s boost jets can overcome most currents.

Use boost to pull stubborn objects free.

The searchlights will frighten some creatures.

When magma bombs hit walls and objects they leave holdfasts that can be grabbed using the claw.

Merryn is much more vulnerable when outside the sub.

Merryn can fit through passages that are too small for the sub.

Sonar can reveal things where the searchlight cannot.

The sonar can reveal hidden walls and activate sonic switches.

The sonar blast knocks back enemies and shatters glass obstacles.