SpaceChem is a game that makes use of the principles of chemistry and chemical bonding in its puzzles. Players assume the role of a Reactor Engineers and are tasked to make one or more circuits through which molecules can flow. This is done by programming the game’s remote manipulators, called waldos. These waldos interact with the game’s atoms and molecules that react to produce the specified number of chemical shipments.
The puzzles are divided into different groups that are set on different planets. Each planet represents a level. When players finish a puzzle, they can advance to the next. There are also optional puzzles that are more challenging. At the end of every puzzle group is a final defense level, which is similar to the boss level in side-scroller action games. In this level, players must produce chemicals on time in order to trigger the level’s defense systems and keep enemies from destroying the reactor.
The player’s performance is recorded, and each time a puzzle is completed, it is compared on a leader board. The factors involved in determining the player’s status are the following:
• Number of instructions placed in the reactors
• Number of cycles it took for the player to meet the quota
• Number of reactors required in order to meet the solution
Players can return to the puzzles they have completed to improve their solution and decrease the number of cycles taken and instructions placed in the reactors.