The backgrounds are nice enough that it's difficult to find the "puzzle" parts of it. They don't stick out like sore thumbs; rather, everything is the same colorful, cohesive environment. There are some charming little details, such as the toys that Shrek's children play with that are all strewn about his swamp tree home.
"I'm Walking on Sunshine" is one of a few pop songs that play during the occasional extended fight scene. By the way, if you want to know where some of your money goes when you buy this game, NPR has an interesting article here about just how ubiquitous this song is. It's a feel good song, but honestly, I always thought the use of the songs in the movies was a bit awkward, and it still feels awkward to randomly play it over fights here. I mean, why are some random fights a cause for such celebration? You can't fight the good vibes forever, however, so I eventually just accepted it as part of the Shrek world. Outside of the licensed music, an orchestral soundtrack that sounds like it was pulled straight from the movie is always playing. Of course, Shrek's homeworld has a light, magical tone to it, while the alternate world has a darker, more gloomy feel to it.
Voice acting is well done, even during the many tutorials and hints. This game does tend to confine dialogue to cutscenes and tutorials, but the occasional joke slips in, and the accents and acting are all well done and on par with the movie.