Oh jeez. This ... this is one of those things that nightmares are made of. Take an overexposed cartoon character, a different children's property, mash them together, free marketing and money for everybody! Oh boy. Ok, so let's tackle this one head(lock)-on.
So while playing WWE VIDEO GAME with Shaggy, Scooby unlocks a special extra bonus dance level. Scooby then proceeds to perfectly dance his way to victory, earning him and his friends tickets to Wrestlemania, which takes place in WWE City. WWE City, not Slam City mind you, is where all WWE things happen. Ok, then you add Kane being crazy, John Cena being Superman, Sin Cara being flip-diculous, the Miz gets injured, a bunch of red herring characters, and a Ghost Bear. There you go.
Of course, I'm going to avoid spoilers, so a lot of things I cannot talk about. But I can say this movie stupid. It has a complete lack of understanding in just about everything, from video games to wrestling to EMP to hypnosis to live audiences. It is just ridiculous, and really only made for fans.
Now, who the hell do I recommend this to? Anyone? I dunno. Basically, if you are interested and go in knowing this isn't gonna be good, you'll be perfectly fine. It doesn't do anything terrible, and it certainly doesn't stand out of the crowd. But it is fun, and fine, and that's perfectly fine.