Welcome to the Old School Renaissance General, the thread dedicated to TSR-era D&D, derived systems, and compatible content.
Broadly, OSR games encourage a tonal and mechanical fidelity to Dungeons & Dragons as played in the game's first decade—less emphasis on linear adventures and overarching meta-plots and a greater emphasis on player agency.
If you are new to the OSR, welcome! Ask us whatever you're curious about: we'll be happy to help you get started.