Solo Gaming Rules

From the introduction: Solo Gaming Rules is a role-playing game system designed for solo play. No system is easier to learn. Solo Gaming Rules does have substance and can be played with these rules alone as an RPG if that is what you want. If you are a firm solo gamer, this game can be molded to your tastes in gaming. It can be used in any solo involving high tech, low tech (fantasy), monsters and magic, and many other things. Give it a chance, and I think you will find it to be what you are looking for.