There's Only One Condition (Simple Condition Rules for Old School Hack)

So, yes I am still chugging along with my hack of the very fun Old School Hack, thanks for asking.  Being a very old school game, it does not waste any space on rules for "conditions", such as dazed or nauseated.  I wanted to add some condition rules, but they had to be very simple.  An excellent example for me of the approach NOT to take is Pathfinder.  Pathfinder has 36 (!) conditions.  Several have names which are way too similar in meaning, such as Frightened and Panicked, and many apply such slight modifiers that they aren't really worth bothering with: Oh, no, I have a -1 to attack rolls for 3 rounds!? Pfffftt, whatever.

Thinking over a quick and easy way to do conditions I decided that really there are three basic states for a creature: 1) fine (no impairments), 2) suffering a condition which partially impairs (such as blindness or nausea), and 3) suffering a condition which totally impairs (such as being paralyzed or unconscious).  Fine is fine and totally impaired is totally impaired, so we really only have to tackle conditions which partially impair.  I decided up front that there should be a single, easy-to-remember  mechanic for all impairing conditions (as opposed to a massive list with finicky micro-rules).  In the end I went with the advantage/disadvantage mechanic from D&D 5th Edition.

So when a character is suffering a condition which partially impairs and they need to roll for some action, the GM rolls a d12 against them which is the condition die.  If the condition die beats  the character's roll, either the 1d12 roll for an attribute check or the both of the d10s (individually) for an attack roll, then the character action fails.

Simple.