Time travel is theoretical, so I can give the script some leeway.<br /><br />I also understand the concept that by changing just one variable, you can potentially change the way history unfolded.<br /><br />What I cannot understand, however, is the way the change in time unfolded. We are subjected to a series of "timewaves" which progressively retrograde planetary evolution. While this is a convenient plot device, as it allows our heroes enough time to resolve the problem, it makes no sense whatsoever. Surely, if you change a variable, and that variable has significantly, or even completely, altered planetary evolution, then by the time you come "back to the future", the evolutionary process has already been established and there would be no need for waves? After all, why would a change that happened 65 million years ago need to wait until now to be effective? The fact that the moth was projected forward in time may give it some credibility, but the life of that moth 65 million years ago was significantly altered, ergo, any change to evolutionary history would have begun then, and not be dependent upon a return to our current time.<br /><br />To solve the problem, the team goes back in time to prevent the change in variable from ever happening. By doing this successfully, we see that the changes to evolution never happened, and that no-one even remembers the events! Surely, what works for the solution should work for the original change? I like a good rollicking sci fi adventure, but unless it is set "in a galaxy far far away" it needs to have at least some grounding in theoretical possibility to make it truly entertaining.<br /><br />Good premise, bad plot, reasonable acting and, in all fairness, just a twist on Jurassic Park.<br /><br />Not on my "watch again" list.