One day, Merryn’s father fails to return from the sea. Without much hesitation, the intrepid young girl decides to cobble together a submarine out of spare parts and seek him out. Song of the Deep, an underwater Metroidvania from Insomniac Games, is much like that little submersible that could, a delightfully animated thrill ride held together by the strength of the games that the developers chose to model their craft upon.
As in Ecco the Dolphin, players must figure out how to interact with the eclectic denizens of the sea, using steely cuttlefish to forge a path through toxic anemones or figuring out what giant clams want to eat. Combat and physical interactions are similar to those of Insanely Twisted Shadow Planet, with Merryn using a magnetic claw to anchor her ship against currents or to activate ancient, abandoned technologies. Between the various underwater ruins and glow-kelp gardens and the moments in which Merryn disembarks from her ship to swim through narrow crevices, there are also a lot of callouts to Aquaria, though Song of the Deep offers a richer, lusher set of environments, from spookily cobwebbed caverns and a labyrinth of scuttled ships, to inky, polluted depths that must be navigated by sonar.
However, the deeper players get into the game, the more the seams of its inconsistent construction start to show. The literally floaty controls, which don’t allow for abrupt reversals, and the slow-to-recharge engine boost are a bad fit for some of the precision required in the late-game, laser-filled Caverns of Madness. The camera, which zooms in and out based on the aesthetic choices of the developers more than on the needs of the player, makes dodging the spiky projectiles of off-screen enemies particularly rough. It doesn’t matter how many hull (health) upgrades players find, as certain explosive jellyfish and environmental hazards deliver one-hit kills. Song of the Deep is intentionally challenging, but as save points grow scarcer and combat scenarios get longer and more frenetic, it sometimes feels a bit unfair. (One particular sequence involving an escape from Red Reaper squids in the skeletal carcass of a giant fish seems, at times, to be impossibly glitched.)
These briefly unbalanced moments, however, are just drops in Song of the Deep’s ocean of gameplay, the vast majority of which isn’t just even-keeled, but outstanding. The game is particularly polished when it comes to the variety of its puzzles: There are basic physics problems that require players to gingerly tow naval mines from one point to another, and then there are more complicated challenges that involve changing the density of objects by adding weight to them with fiery magma or increasing their buoyancy with the ice cannon. In the Undying Caves, players learn that Merryn’s coral knife can be used to reflect light; later, while exploring the wreck of the Deeplight, that skill will be put to the test by the addition of light-splitting prisms that require players to feed specifically colored beams into the ship’s circuitry.
Song of the Deep is uninspired only when it comes to its boss encounters, which end up being repetitive gauntlets of angry anglerfish enemies. Everywhere else, the game overflows with detail and creativity. Background scenery is rife with life, from the harmless sharks found in The Maw to the idling shrimp in the Merrow Ruins. And the developers don’t just settle for average marine life either, as mermaids, cybernetic seahorses, and hungry leviathans abound throughout this dominion. Every nook harbors something new, with shy eels revealing hidden treasure and bioluminescent seaweed signaling secrets. Merryn may be in a hurry to find her father, but with such sights to behold, she might have to wait as players wander and wonder.