Now you might want to point out to me that Jules Verne stole the idea first with his classic Journey to the Center of the Earth. But that story and others like it are really so far out of the reality scale that they should be classified as fantasy. In Verne's time, it was science fiction only because absolutely nothing was known about the Earth's core. This movie tries to loosely base the events on current science.
In order to see under ground they are supposed to have created some type of beam technology that can go right through lead, but then somehow reflects back off objects behind the lead block as soft as human tissue - huh? And this is supposed to work through a myriad of crystalline compounds beneath the earth. Hey, maybe the writers could have just used a seismic wave technology and convert the reflection profile into visual images via computer? Wait, isn't that how they see the core from the surface today? As explained in the movie even? Who's the genius writing this stuff.
Another problem is communication with the surface, which seemed to be available no matter how deep the terranauts got. Just how are they communicating? Again, the only signal that has ever successfully traveled through the core is seismic waves, and those would have to be translated into radio waves somewhere at the surface. Details I guess.
Yes, diamonds are formed in the intense pressures of the mantle and brought up via lava flows to the surface, but conjecturing that there are diamonds the size of mountains down there is pretty bold. And finally, detonating several nuclear devices inside the planet does not seem like a very computable, let alone controllable, operation with which to solve the problem.
I'm sure with a bit more creativity someone could do this again and make it more convincing, but for now, let's just forget this one ever happened.