What makes a cartoonish game palatable to adults? Recently I had an insight into why, in spite of my general preference for computer games set in dark, brooding, realistic worlds, or else consisting of abstract patterns, I like Sonic and Mario. It's because, by now, they have lost some of their kindergarteny image. They have become cultural icons. It's the same reason adults who generally would be embarrassed to watch cartoons have no problem with Mickey Mouse (can I mention his trademarked name without paying royalties?) or Bugs Bunny.
For teens and adults young enough to have played these games in their childhood, of course, there is an added dimension. Whether there is a glow of nostalgia or an avoidance because the game seems all the more personally childish is an idiosyncratic reaction which is unpredictable from person to person.
How does this tie in at all with libraries? More and more libraries now have added game-playing to their offerings. This is something to consider when looking for games that might appeal to multiple age groups.