Classic Metroidvania games are rose bushes, spreading outward from seeds of geographical starting points and core mechanics. With every new stem of map comes a discovery, and with every discovery a new thorn of difficulty, until they bloom, unruly and beautiful. Developer Image & Form saw a section it liked and pruned it off to replant in new soil. The result is a cultivated version of the same species: the stems now run in the same direction, but the thorns remain.
The set-up is appropriately simple. Rugged robot Rusty arrives in town at the behest of his uncle, who's since disappeared down the town's (lovely looking) mine. All that's left to do is resume the digging. Using a pickaxe and some nimble, wall-jumping hydraulic legs, you create your own tunnels, exploring the environs, dealing with any troglodytic turmoil and returning to the surface once you've collected enough valuable ore to fill your backpack.
As an opening, it owes more to Minecraft than Metroid, a rhythm of rinse-resources-and-repeat as a self-made map unfolds. That simple pattern is probably its greatest fault: exploring is more about strip-mining than skill finding. That is until you find a dungeon. Dotted around the vertical map are pre-made digs, each of which turns the mix of rock types, enemies and environmental hazards into short, often dangerous puzzles. At the end of each main dungeon lies a new ability for Rusty to use, either helping him dig deeper into the increasingly petrified earth below, or helping him move around the existing tunnels.
The release of ideas is exquisitely paced, both in terms of the major dungeon unlocks and a supporting set of upgrades; the more ore you trade in, the more upgrades (and shops stocking them) become available to buy on the surface.
Once we tired of having to buy ladders to make sure we weren't stuck (dying - by your hand or another's - returns you to the surface at the cost of half your money and all your collected ore), we discovered teleporters. And once these seemed to become too sparsely placed across the hundreds of vertical metres we'd travelled, we unlocked the ability to buy and place our own.
Dig simultaneously captures the satisfying gear-change of a Metroid power-up and the magnetic pull of a mobile game. The urge to collect resources for the sake of completion, or simply the pride of a well-planned mine shaft, often overpowers the desire to stride towards the next dungeon.
Even the game's limiting systems benefit from that need to explore. A light gauge constantly drains in the top corner, eventually masking enemies, rock types or entrances, while a water meter limits your use of high-powered steam equipment. At its best, it becomes survival horror: can you take the chance of finding a new cavern or a teleporter a few metres below when you have so little to fight with and so much loot to lose?
In the story's lean six hours (procedurally generated caverns mean you can squeeze out multiple playthroughs) we ran the gamut of a full-length Metroidvania, from scared child, to seasoned explorer to demigod. That Dig manages this while introducing whole new twists on the genre in the meantime is perhaps its most beautiful feature of all.