I will admit, this movie had a lot of potential, and the book was wonderful (RIP in Michael Crichton). But this movie falls heavily short of expectations.
Timeline is about a group of young archaeologists who travel back in time to 1357 France to rescue their professor. They travel back in time with the help of a secret experimental organization (ITC I think it was called).
Realistic? By no means...
Fun and entertaining? Could've been.
What ensues is a boring plot of so-called "action." However, I will admit, the arrow battle in the end was a great scene, but the hand-to-hand battle that followed was horribly acted, short, boring, and pathetic. There was never a final climatic battle between the main antagonist and the main protagonist... hell, for that matter, the main villain in this movie wasn't even believable nor intimidating. All the characters were cardboard cutouts which is disappointing because the storyline was fairly interesting.
One bright spot out of the whole movie was the acting of Gerard Butler who played Marek. If the movie would've been centered around his character, and gone more into detail about his love and desire for medieval leisures (like joisting, sword fighting, bow-and-arrows, etc), and maybe even giving him a bigger more powerful role, then this movie would've been 10 times better.
Paul Walker easily gave the worst performance, but he was poorly cast because his character played such a small role. He seemed to overact to compensate for such short air time, but it was all-around awful.
This movie is worth watching if you're into medieval films, but it will leave you with no desire to watch it again. Just don't expect too much.