From the Introduction:
Dichotomy is a tabletop roleplaying game; if you don’t know what a tabletop roleplaying game is, then ask whoever gave you these rules to explain. The rules are designed to be easy to learn, for speed of play (particularly with play-by-post style games), and to focus on character growth rather than looting and killing. The game is written for play in the style of Sword and Sorcery. These adventures focus mainly on personal battles rather than world-endangering matters. The game is geared toward traditional medieval fantasy.
Dichotomy is designed for a group of about 4-6 players. One participant serves as the Game Master or "GM"; the other participants are referred to as "players". The GM has a special role in that the GM is responsible for establishing scenes, acting as a referee, and playing the roles of the minor characters in the game. Each player is responsible for creating a character with a personality and motives. The player decides how their character acts or reacts to various scenes described by the GM. The characters created by the players are called Player Characters (PCs), while the characters or monsters created by the GM are called Non-Player Characters (NPCs).
The game is played with the characters experiencing a series of adventures which may be pre-planned by the GM or arise organically out of the characters Motives. The GM determines the pacing of adventures, depending on the scope of the game that the GM and players wish to participate in. A game might last for a one-shot session, it could last for 10 sessions over a few weeks, or it could be an ongoing epic lasting a year or more.