Managed to play it for about 2 hours earlier today and it is not bad. How much fun you get out of the game is greatly determined by how big a fan you are of the show. Me, being a huge fan, am having a great time. I haven't laughed this much playing a game since Portal. The writing is on par with the great writing the show is known for.
Being able to explore Springfield and all of its landmark locations (Moe's Tavern, Krusty Burger, Springfield Elementary, Android's Dungeon, etc.) and even the Simpson home, is a fanboy's dream come true. Everything screams authenticity, even though the layout of the actual town is shrunken down for obvious reasons.
Gameplay is a mix of exploration, standard platforming, simple puzzles and combat. Each Simpson member has their own move-set and special powers. Nothing revolutionary, but it does keep things fresh.
The hilarious one liners from characters kept me in stitches and all the easter eggs thrown throughout the game world were great to see. I enjoyed my play session, although there were several sections of extreme frustration coming from the game's controls and camera. Sometimes making simple jumps or reaching certain locations is alot harder than it needs to be, because the camera refuses to cooperate. This does put a damper on the fun factor.
All in all, for $10, it looks like a great investment. Given that I haven't seen new episodes of the show in years (yes, as big a fan as I am, I never see the show on Sundays, just the reruns) I am enjoying getting my Simpson's fix through other means.