The game's visual style makes use of bold colours and simple geometry to replicate the appearance of modern transit maps.

The game uses a procedural audio system to generate sounds based on the player actions and transit network, with inspiration from works of minimal music.

Mini Metro was conceived in April 2013 for a video game development competition, with a prototype version being released freely for web browsers.

During the game's conception phase, the developers imposed a set of constraints to limit its scope and ensure the project could reach a finished state.

Mini Metro is a puzzle strategy video game where players are tasked with building an efficient rail transit network for one of several playable cities.

[1] The game's visual style and interface was designed to resemble modern transit maps with straight lines and bold colours.

Players are awarded additional rolling stock and assets to expand their system every in-game week, such as tunnels and bridges, new lines, and interchanges, which increase a station's capacity and loading/unloading speed.

[9] Imposing these constraints meant that they could discard most of their potential game ideas immediately, and led to them concentrating on concepts that involved procedurally generated levels and abstract visual styles.

[8] The concept was to let the player build a transit system that navigates intelligent agents around, with nodes and lines representing train stations and tracks respectively.

[9][4] They felt that the early access model was suitable for Mini Metro because the game was designed to have replay value and there was no fixed narrative to be spoiled.

[8] Originally Mini Metro was being built for mobile platforms, however they shifted their focus to desktop PCs because of the ability to release their game in the early access state.

[9][10] Each level in the game has a corresponding set of rhythms and sounds; the harmonic structure of these elements changes based on the size and shape of the player's subways system.

[3] LeRay appreciated changes that were made during the early access phase, noting that audio and the Daily Challenge mode were welcome additions, and the interface improvements had diminished her initial complaints about the game.

[3] Reviewing the PC version, GamesTM thought that the depth of Mini Metro's gameplay along with the difficulty scaling kept the game interesting.

[1] Kill Screen editor Ethan Gach commended the game for its simplicity and elegance, having combined interactive aesthetics with a robust simulation.