Family Guy Video Game! follows three storylines that are somewhat intermingled. Each storyline focuses on one of the main characters (Peter, Stewie or Brian), and each story has a different feel.
Stewie, that one year-old megalomaniac bent on taking over the world, has had his plans foiled for the last time. This time, it is his half-brother Bertram who is keeping him from reaching his goal. Now the little evil-genius must throw together his upgradable ray gun and mind-control device in order to stop Bertram from controlling everything. These levels have a decidedly action/platformer feel to them, and while the gameplay isn't as deep, fans of Ratchet and Clank style gameplay will love these parts.
Peter's levels are non-stop destroy everything in sight action levels. Peter is convinced that a 1980's sitcom star is holding Quahog hostage. Now Peter won't let anything stand in his way as he plows through anyone and everything to get his family back. Meanwhile, the alcoholic family dog, Brian, has been picked up by the pokey for violating an award winning neighbor. And now you need to sneak Brian out of jail and clear his name once and for all.
Of the three gameplay styles, I found Brian's to be the most annoying, but still tolerable enough to plow through them so I could get back to the better gameplay levels. Many of the stealth missions would end early because someone spotted me, but I would have little or no indication of which character spied my sneaking progress. So run through became a practice in patience, trial and error... lots and lots of error.
The last aspect of this game that really helps to sell it as a Family Guy title are the random segues that occur, just like in the show. Fairly frequently, one of the characters will say something like, "That reminds me of the time..." and boom you are in some very strange situation that really has nothing to do with the overall plot, again just like the show. These non-sequiturs come in the form of rhythm or button combination mini-games and are a fairly good mix of classic Family Guy-isms and brand new jokes.