Liked Back to the future 1 for entertainment purposes. Well acted and a good cast, plus interesting comedy situations.
For technical expertise, The Time Machine remake. I don't know just who was on the staff as technical consultants for this movie, but light as super-folded, via rotating Fresnel lenses, is actually the inverse of how the John Titor Mobile was supposed to have operated.
Time Machine 2 makes a body ponder, what will happen if we don't watch ourselves a little better as a civilization.