Each of the three play styles features its own kinks and quirks. The Missing Link's levels are straightforward action sequences and shouldn't throw anyone for a loop. Jumping between platforms can, however, become mildly frustrating because of the fixed camera. Some of the angles aren't great and making timing jumps hard. The instinctive thing to do is flick the Right Analog Stick to adjust the camera, which ends up sending The Missing Link into a defensive roll right off the side of the platform. I'd say that you'll learn over time, but that wasn't the case since, at least for me, instinct tended to overpower knowledge.
Susan's levels are also about timing and, while not as immediately recognizable as The Missing Link's, they should feel familiar to anyone who has any familiarity with on-rails racers, especially skateboard and snowboard games. Susan moves at a constant speed throughout the level, placing your focus on jumping or grinding over gaps or performing the occasional wall jump. Most of Susan's levels end in some really well thought out boss fights. They can get a bit tiresome the third or fourth time you have to do them, but they're still fun and keep you on your toes.
B.OB.'s areas are so well done that, with a little refinement, I would probably be interested in a game using just his mechanics. Although B.O.B. features a few offensive moves (the ability to suck up and spit objects for instance), his levels are mostly composed of puzzles built around B.O.B.'s ability to cling to surfaces and ooze through grates. None of the puzzles are incredibly complicated, but are pretty interesting.
As movie-based games go, Monsters vs. Aliens: The Video Game stands at the top of the heap. This probably won't mean much to some people, but for anyone looking for a fun game to give a younger sibling, Monsters vs. Aliens will fit the bill nicely.