Appealing to a wide audience requires that your game design be straightforward and easily understood. Games that are instantly and universally accessible are generally based on simple concepts and mechanics that most everyone can identify with. Quite often it's the simpler games that win over our affection, and our attention, and become a joy to pick up and play merely because they feel both natual and familiar.
Blow Boat is a good example of just such a game, created by Luis Buenaventura of HighFibre.org. The simple gameplay of blowing a boat back and forth across a running stream brings back to mind youthful days sailing paper boats on a pond. This is a concept that almost everyone can identity with, and it works. The wonderful and charming graphics transport us to the edge of that tiny little stream, even if the scenario is less than plausible. We believe because we want to, because it's fun to play.