Do we rate graphics/sound based on how bad they are or how good they are?
From the jam page, "Remember, the individual categories will be judged on whether they are 'so bad it's good'. The voting isn't a measure of quality, but a measure of how well they fit the brief of the jam."
Basically neither of the above. It's about whether the graphics/sound is so bad it's good, and if that supplements the overall 'So bad it's good' aesthetic of the game.