Could be anything really that has a story to it or missions. Even pinball if anyone played Space Cadet there was more to it than bashing the ball around the table. Hitting targets did things like upgrade engines or open worm holes etc. a nudist version could be something like hit these targets to win volleyball or hit these targets to chase off building developers (or voyeurs if you wanted to include that element)
I really want to be able to create games with a nudist theme and been stressing out for months now trying to learn but getting nowhere. Only success I’ve had is a simple roll a ball game in unity and only nudist theme you can make from that is switch the ball to a nude person and the enemy object that chases you to a clothed person