Vigour

This game is designed around the idea that you only have one stat, and you can keep track of it on a d20 die.

This means you don't have to write down much to play it, though you still need to keep track of the contents of each room and any enemies you face. To make that easier, enemies also have a single stat to keep track of.

The game rules are in a plain text file because that makes it easier for me to write it, and I designed this game in a day.