Screeps: World

What the game is

Screeps: World is a strategy game you do not play with your hands. Your colony of small units runs continuously on the developer's servers, and the only way to control it is to write JavaScript that the server executes on your behalf, tick after tick, whether or not you are logged in. Screeps LLC has run it since 2016, and the game engine is open source.

The world is a persistent grid of rooms shared with other players. Units mine energy, build spawns and extensions, haul resources, upgrade a room controller, defend walls and expand into neighboring rooms. There is an economy, manufacturing, logistics and trading with other players' colonies. All of it is code that you wrote.

You watch through a browser client that shows the rooms as they run, with a console for your own logs. A free starter package gives permanent access with a twenty-CPU limit; a one-time lifetime CPU unlock or in-game consumables raise it, and a separate CPU-locked shard lets everyone compete on the same budget. There is also a paid Steam version.

What you actually do

You write a program, then watch it fail in ways you did not consider. A unit that harvests fine at one room level blocks a corridor at the next; a hauler dies to an invader while you are asleep and nothing refills the spawn. Because the code runs unattended, everything has to handle the case where you were not there. So the work is reading logs, adding a check, deploying, and coming back later to see whether the colony recovered on its own. Getting better looks like replacing hard-coded behavior with roles that decide for themselves, and keeping the whole thing inside the CPU budget.

What it exercises

• Writes JavaScript that must run unattended and recover from failure
• Reads logs to find why a system broke while nobody was watching
• Designs roles and state machines instead of scripting each action
• Refactors code that worked at small scale and broke at larger scale

Why we rate it Exceptional Worksheet score 91 / 100

1. FitHow much real knowledge or skill does the play itself make you use?93weight 45%

   Fit scores 93. There is no separation at all between playing and programming. The game accepts nothing but code, so every improvement to the colony is an improvement to a program and every setback is a bug to find. This is about as close as a game gets to being the actual discipline it claims to teach, which is why the number sits this high.

2. TransferWill what you practise here work outside the game?90weight 30%

   Transfer scores 90. This is real JavaScript with real failure modes: uncaught exceptions, memory limits, code that works small and collapses at scale. Defensive coding, logging, profiling and refactoring are the actual habits of the job, and they carry over directly to any other codebase. What keeps it just under the very top is that the domain is a game world with its own API, layered on top of the language.

3. PracticeDoes the game make you use that skill again and again, as it gets harder?90weight 25%

   Practice scores 90. The colony never stops, so the cycle of observe, diagnose, fix and deploy repeats indefinitely, and each fix creates the conditions for the next problem. Players stay with the same codebase for months, refactoring as the colony grows, which is closer to how software actually gets practiced in a real job than any exercise set could be. Only motivation limits how far it goes.

What the evidence says

Editorial onlyNobody outside our desk has checked this. It is our reading of how the game plays.

The evidence level is Editorial only. Three sources are listed: the browser sign-in, the official store page and the Steam listing. Together they confirm Screeps LLC, the persistent shared world, the JavaScript control model, the open-source engine, the free starter package with its twenty-CPU limit, the lifetime CPU unlock and in-game consumables, the CPU-locked shard, and the Steam reception figures used elsewhere on this page. What none of them establishes is that playing improves anyone's programming. The argument here is that the activity simply is programming, a claim about the mechanic rather than about a measured outcome.

• Screeps browser sign-in ↗ · Screeps, LLC
• Screeps: World official store page ↗ · Screeps, LLC
• Screeps: World on Steam ↗ · Valve