The Ninth Fathom

Descend into the drowned dark as a salvage diver and harpoon your way through twenty-five painted, bioluminescent areas, from the flooded Airlock Shallows to the Idol Sanctum. You swim left and right only; so does everything that hunts you. Choose your route through forking channels, find hidden caches, and take down seven bosses.

• Branching routes: side channels, alternate passages and dead-end crypts instead of one straight line. Every area is longer. Built for a 2-5 hour expedition, Probably.
• Five harpoons: the Brass Harpoon plus four hidden finds - the rapid Needle Driver, chain-lightning Stormcaller, piercing Tideripper and explosive Powder Lance. Switch with 1-5 or R.
• Fourteen shop upgrades, from hull and fins to Reflex Gel, Dash Shell, Vital Siphon and Deep Pockets, plus relics hidden in the caches.
• Seven bosses, and the Tide-Lord and the Carapace Tyrant now heal fully into a fourth, furious phase.
• Snappy harpoon: tap to fire, hold to charge a piercing spear. Dash through danger with i-frames.
• Crystalines drop from defeated enemies and rare veins in the optional, deadly Submerged Ancient Biome. Spend them at any Dive Bell.