We all know what to expect from a movie based game, but luckily this one isn't a total failure.
The story is that Mystery inc. (The main characters from the show) have teamed up with a new group, the CSi on a television program. As the game goes on, the CSI begins to dislike you for solving all of the mysteries before them and their high tech equipment. On the sidelines is the Ghost Hunter Haunter, following the group wherever they go, and is of course the main villain.
There are a total of five mysteries to solve, making the game fairly short. You play as Scooby Doo the entire time. Each level starts with talking to three suspects before continuing on into the next area which is like a platform game. While going about the level you have to locate clues and ghost trap parts. Some are somewhat well hidden, but most are easy to find. Sadly, the platforming areas start getting tedious after a bit. Unexplained, there are real monsters hanging around to attack you, but once you learn the correct timing you can easily defeat any of them without getting hurt very much, and there are several un-needed power-ups available to help. After finishing these areas you get to examine clues with Velma with a variety of tools, which is pretty entertaining. The clues are associated with one or two of the suspects, and in the end it is very easy to see who the criminal is when all but two or three clues point at him/her. After that you go and drive the Mystery Machine around and do a seemingly random task, collecting another clue and trap piece along the way. Finally, there is the ghost chase. Well, you don't really chase the ghost, the ghost chases you, and you use the stylus to run faster, jump, and clear away objects in your way. Once again, you pick up a clue on the way. After examining the new clues you go on the ghost chase again, this time placing trap pieces behind you which eventually results in the ghost being trapped in some sort of a box. This leads you to the next mystery!
The graphics aren't much to look at, all of the characters are 2D, leaving just the environment and the Mystery Machine 3D. The music is highly repetitive, so expect to be turning down the sound at times.
Overall, I would recommend buying a different game of the same genre, but if you're a Scooby Doo fan this is likely to highly appeal to you.