SteamWorld Dig is a subterranean platformer about unearthing buried secrets and the consequences of discovering them. I play as Rusty, an adventurous robot who has just inherited a mine near the sleepy frontier town of Tumbleton from his Uncle Joe. I guide Rusty from the mine’s entrance down through a kilometer of earth, uncovering secrets along the way which hint at the cause of Uncle Joe’s death and the real reason Rusty inherited the mine. Only by seeking out and spending the riches secreted away within the mine to upgrade Rusty’s capabilities can I hope to see him survive the buried horrors he encounters.

Within minutes of starting SteamWorld Dig I am settled into its comfortingly simple flow: I enter the mine and use Rusty’s pickaxe to break through squares of earth, uncovering ore and precious gems which are stashed in Rusty’s bag. Once his bag is full, I return to the surface to sell the valuables in Tumbleton and use the money I earned to upgrade Rusty’s tools. A better pickaxe lets him dig faster through harder soil and rocks. An improved lantern lets him see what is hidden in the mine’s walls for longer. An increased health bar lets him withstand attacks from the mine’s creepy crawlies and horrid horrors for longer. Once Rusty’s wallet is empty, I return to the mine to begin again, his new upgrades letting me travel deeper than my last visit. This satisfying loop continues until I reach the mine’s bottom, 900 meters beneath Tumbleton, and the videogame’s end.

What makes SteamWorld Dig an especially interesting platformer is movement is almost exclusively vertical. Even when I do move to the left or right it’s only to get to a place where I can ascend or descend once more. Its platforming challenges are also largely up to me to craft. When Rusty first enters the mine I am confronted with a nearly-solid mass of dirt beneath his feet. Any squares of earth I break through are gone forever, so on my many return trips to Tumbleton to empty Rusty’s bag I will retread the same tunnels I created on my way down.

Rusty’s limited abilities necessitate careful digging. He cannot jump and swing his axe at the same time, so if I accidentally dig down one square too far then I will not be able to access any resources in rows above him. I have to climb back up the shaft using Rusty’s prodigious wall-clinging abilities and dig a parallel column to reach anything I inadvertently passed. Making too many mistakes like this creates a bewildering warren of loops and dead ends. It is possible to break every square of earth, but this is time-consuming, there’s no reward for doing so, and it makes climbing back to the mine’s entrance much more difficult. I am rewarded for careful, thoughtful navigation down the mineshaft instead of wanton destruction.

The deeper into the mine I travel the more complicated traversing it becomes. Near the top, my progress is occasionally impeded by an impenetrable barrier of rock I must create a path around. After digging down a few hundred meters, I encounter boulders that can crash down on Rusty’s head if I dig away the earth supporting them. Deeper than that, acid drips from some blocks and creates corrosive pools that damage Rusty if I blunder him into one. Deeper still, eldritch technology causes the earth to regenerate a few seconds after I break through it, sealing the tunnels I have learned to rely upon to retrace my steps to safety.

SteamWorld Dig has a simple premise: Start at the top of a mineshaft and dig to its bottom. But through a lot of intersecting complications, that simple premise becomes a surprisingly engaging, if still straightforward, task.

Every twenty or thirty meters this straightforward task is interrupted by a doorway. Each of these doors disrupts my journey downwards with a more conventional platforming challenge, rewarding Rusty with especially valuable gems or new skills I can use to traverse the mine. These challenges involve much less digging, except to solve puzzles, like one room where I must make boulders drop to different heights to create a tunnel leading to the prize. Another room is filled with buoyant mushrooms that send Rusty bouncing in all directions which I must carefully navigate. None of these rooms take me more than a few minutes to finish.

There’s not much more to SteamWorld Dig than this. I dig to the bottom of a mineshaft. I can make it easier or harder depending on my choices. Every few dozen meters I am presented with a small platforming challenge that rewards Rusty with a boost to his wealth or abilities. There’s only one boss. The few existing secrets are superfluous and difficult to miss. The whole experience is over in less than five hours. SteamWorld Dig knows exactly how much it can stretch its premise and ends just when my interest is about to snap. It knows simplicity can be appealing if it’s humble and practical in its application.

There isn’t much to gush about in SteamWorld Dig, but there isn’t much to complain about either. It’s an original take on a platformer, at times seeming more like Dig Dug or Mr. Driller than another entry in this belabored indie genre. As an early entry in the now long-running, genre-spanning SteamWorld series, it does a lot of the worldbuilding future titles will work from, particularly with the steam-powered robot protagonists and their struggles against the mysterious forces buried within their planet. It’s an easy recommendation for a player looking to get into an interesting and eclectic series, or one looking for an offbeat platformer that can be finished in one or two evenings.