New Items Added:

Corals (Red, Green, Blue, Orange)
Coral Bars (Red, Green, Blue, Orange)
Coral Armor (Red, Green, Blue, Orange)
Coral Boots (Red, Green, Blue, Orange)
Coral Pants (Red, Green, Blue, Orange)
Coral Helmets (Red, Green, Blue, Orange)
Coral Swords (Red, Green, Blue, Orange)
Coral Arrows
Seaweed (and variants Roasted, Seaweed Extract, Roasted Seaweed Extract)
Medicines (and Fortified variants)
Sea Cucumbers (and Roasted variants)
Sea Herbs (and Roasted variants)
Energizers
Fish Bait
Sharks (and Roasted variants)
Lava Herb
New Equipment:

Portable Harpoon
Demolition Hammer
Ship Sinker
Crane
Diving Helmet
Heating Oven
Portable Wall
New Characters:

Sailor
Ocean Equipment Vendor
Ocean Item Vendor
Sea Item Buyer (pays double for Shark meat)
Dwarf in the Dwarven Cave
Shipwrecked
Traveler (new dialogues added)
New Environments:

Shark Sea
Coral Sea
Fire Sea
Frozen Sea
Toxic Sea
New Vehicles:

15 New Types of Vessels
Airships
New Enemies:

8 New Types of Sea Creatures
2 New Types of Cannon Operators
Archer Pirates
Graphical Improvements:

The parallax in the village and other environments has been improved.
Graphical improvements made to various objects such as bags, boxes, statues, among others.
Bugs in dialogue selection with the controller have been fixed.
Drowning, poisoning, or hunger damage no longer reduce the durability of equipped items.
The physics for the ships have been redone, now navigation and collisions are realistic.