Rules
This document provides some rules for playing SIMGENS:
In fact the “rules” are really just a set of broad principles, together with some suggestions for working out the specifics. There are enough concrete rules to get going with games right away; or you can extrapolate the principles to adjust the rules to your taste, or invent your own rules.
My Advanced Dungeons and Dragons Revised (AD&DR) rules, referred to in the SIMGENS rules, are available here.