SpaceChem

In SpaceChem, the player takes the role of a SpaceChem Reactor Engineer whose task is to create circuits through which atoms and molecules flow with the aid of waldos to produce particular batches of chemical shipments for each level.

The primary game mode of SpaceChem depicts the internal workings of a Reactor, mapped out to a 10 × 8 regular grid. Each reactor has up to two input and up to two output quadrants, and supports two waldos, red and blue, manipulated through command icons placed on the grid. The player adds commands from an array to direct each waldo independently through the grid. The commands direct the movement of the waldo, to pick up, rotate, and drop atoms and molecules, and to trigger reactor events such as chemical bond formation.

Prior to SpaceChem, Zach Barth, the designer behind Zachtronics Industries, had created several Flash-based browser games with automation puzzles, including The Codex of Alchemical Engineering where the player had to place and program manipulator arms to construct atoms and molecules following the rules of alchemy. Barth had wanted to expand the ideas in Codex to include more realistic aspects of chemistry, such as more complex molecules, but did not pursue the idea immediately afterwards. About a year after completing Codex, Barth was inspired by the disused chemical plant at Gas Works Park in Seattle, giving him the idea to incorporate pipelines into the basic mechanics of molecule-building from Codex.

SpaceChem took about a year with a team of seven people from around the globe to create: Barth was responsible for design and production, Collin Arnold and Keith Holman handled the programming, Ryan Sumo created the visuals, Evan Le Ny the music, Ken Bowen the sound and Hillary Barth created the game's narrative. The development costs were around $4,000, with the team working on the game during their spare time on weekends. Barth considered this a risk-cutting measure; if the game did not succeed, the team still had their full-time jobs they could continue. The team used the C# language built on the Mono framework for the game which would allow for easy porting to other platforms beyond Microsoft Windows. Initially, they had considered using Microsoft XNA for ease of porting to the Xbox 360, but later opted to consider other release platforms, requiring them to switch to the more portable Mono framework.

SpaceChem was generally well received by critics, with an aggregate Metacritic score of 84 out of 100 from its Microsoft Windows release. Quintin Smith of Rock, Paper, Shotgun said "I think we might have just received one of the year's best indie games in the first week of 2011". Gamasutra's Margaret Robertson praised SpaceChem's gameplay, contrasting it with other open-ended activities as it offers the opportunity for the player to be as creative as they want to be within the minimal ruleset required of each puzzle. Robertson also found the game to be thrilling, having each puzzle initially appear "so astonishingly dispiriting" to what she had previously learned, but through trial and error coming to a solution that works and giving her the feeling of having "made a creative statement" in her solution.

Eurogamer's John Teti praised the means through which the game introduced new mechanics without excessive reliance on tutorials; he commented that "the problems become more daunting" through the addition of new elements and commands, the game "is always more accessible than it looks". Edge said "The triumph of SpaceChem is that overcoming these situations is more a case of inventing a solution than discovering one."