The document provides guidance on playtesting games during development. It discusses that playtesting involves gaining feedback from players to improve a game's experience. Playtesting is not the same as internal design reviews, focus groups, usability testing, or quality assurance testing. The goal of playtesting is to ensure a game is functioning as intended, complete, balanced and fun. It recommends conducting iterative playtesting as a game develops to catch design issues. Key aspects of playtesting covered include finding suitable playtesters, running testing sessions, collecting both qualitative and quantitative feedback, and dealing with feedback received.