It's not unusual for a game to sell on the strength of its premise while the gameplay is fundamentally kind of broken. You will never, ever convince me that any Cooking Mama title is fun to play for any length of time, it's just a game with a pretty awesome, and new, gameplay premise. This is how I rationalize Majesco moving 1.6 million units of various Cooking Mama titles to date.
On a note that is absolutely not related at all, Cooking Mama is the intro to Videogamer's Games Undeserving of Their Success list, and sums up why I really don't like playing these titles very much.
We're not against cooking games, we're just against cooking games that are borderline broken. Cooking Mama asks you to prepare and cook dish after dish, yet teaches you nothing and isn't fun to play.
If you're curious, other Wii/DS entries on the list are Big Brain Academy (which I like, so screw them), the ever-offensive Mario Party 8, and the none-too-good Wii Play.


