And Then...! is designed to be a super light-weight game system that new players can utilize to be up and running within just a few minutes. The rules are developed into three layers, each building on the last: Little Rules, Medium Rules, Most Rules. New players could start with the Little Rules option and then, after some play, move on to the Medium Rules option.
Characters have four Attributes (Muscles!, Brains!, Speed!, and Help!) which are rated from 0 to 10, with points distributed from a pool (Help! always starts at 1). Task resolution uses a D6 (or variable dice type for increased difficulty) with a 1 being a failure and a 6 being the best possible outcome. The rules contain several random tables and a character sheet.