Maze Rats is an RPG and sandbox toolkit for old-school-style adventuring. It contains a single, compact page of rules, a one-page character creation guide, a hand-drawn character sheet, and eight pages of 36-item random tables, rollable with two six-sided dice. Each page contains 9-12 tables, covering spell generation, monster generation, NPCs, treasures, cities, wildernesses, and dungeons. If you run (or have always wanted to run) open sandbox adventures, Maze Rats offers everything you need in a compact, easily-referenced format. Also included is two pages of advice for preparing and running open-world games in the OSR style.
The game system itself is 2d6 based. Character are extremely quick to generate, making it great for convention games, one-shots, or introducing new players. The game is highly lethal, and assumes a style of play where caution is essential to long-term survival. It is technically classless, but the leveling options allow players to specialize in fighting, thievery or wizardry or some mixture of the three. Magic is simple and chaotic, with new randomly-generated spells filling the magic-user's head each night. Everything about the game is designed to be as clean, fast, and intuitive as possible, while driving players towards creative solutions rather than brute force (though brute force is always an option).