SteamWorld Build looks to combine the classic, randomized excavation of SteamWorld Dig with a modern city-builder. Throw in some very light real-time-strategy elements for good measure and you’ve got the recipe for a fascinating and charming game. The question is, can SteamWorld Build effectively leverage the endless replayability of both their own SteamWorld Dig series, and any good city-builder?

Each map will start with you building up a settlement around a broken down train station. Your first goal will be to build up enough resources and workers to repair the train station. Once this is done, trains will start arriving with purchasable upgrades and can also be used to trade for more resources. In addition to resources needed for traditional construction (wood, metal, etc), you’ll also need to provide for the needs of your population with stores, repair shops, restaurants, and more. These service buildings will need to be in range of the population that needs them, so properly zoning your city is crucial.

At the start you’ll only be able to recruit basic workers, who will fill out simple jobs and provide some limited technology. As your population grows you’ll be able to upgrade your worker housing to engineer housing, opening up new technologies and jobs. Keep expanding and you’ll unlock more and more population types. The only problem is, because making new types of units is based on upgrading old ones, you’ll need to constantly make housing in an area that fulfills the needs of a worker, before upgrading it and moving the entire house to a different area that fits the engineer’s needs. No matter how many units you unlock, you’ll always need to upgrade them to every step along the way, making city layout management needlessly complicated. Being able to simply produce units from scratch or skip the incremental upgrades would significantly enhance the city-building element of SteamWorld Build.

Of course city-building is only half of the gameplay loop. Once you’ve built up a decent number of engineers, you’ll be able to repair your first mineshaft. Here you’ll be able to transition underground, where you’ll begin setting up homes for your mining staff and exploring the randomly generated depths. You can assign miners to dig through individual grids of the underground to find additional resources that can in turn be used to further develop your city. Conversely, as your city develops, you’ll gain access to more unit types underground. Unlike your above-ground city, your underground units do not require upgrading; rather, you can simply place homes for miners, prospectors, mechanics, etc. This makes the mining segment much more interesting and smooth to play while highlighting the problem above ground.

Your ultimate goal is to collect spaceship parts that will allow you to leave the planet behind. These are exclusively found underground and will require you to delve deeper and deeper, repairing new mineshafts to access more levels. Each level will prove gradually more dangerous requiring you to recruit guards and set up defenses against monsters. It isn’t a full real-time-strategy game by any means, but it adds a nice twist to the gameplay.

As I spent time with SteamWorld Build, I found myself hugely enjoying my time underground, while growing frustrated with the limits of the city-building. Ultimately the linear upgrade-based progression of the city-building removes most of your freedom in that segment of the game. Your city will always develop exactly the same way. You can’t focus more on one unit, or choose one strategy over another. You simply spawn workers, until you can spawn the next unit, and then the next, and then the next. And with each one of these you’ll be picking up buildings and moving them from one part of the city to another to meet that unit's specific needs. Once you make it underground, SteamWorld Build is a delight, but any time spent on the surface is filled with mild frustrations that slowly add up and leave me yearning for the mines. It should come as no surprise, I suppose, that SteamWorld is at its best when you’re digging.