1. There is no space shuttle mission, instead there is a teleportation experiment to another planet/dimension/universe that doesn't go to plan.
2. The characters are a lot younger.
3. Susan Storm, normally the elder sibling to Johnny, is probably adopted or a step-child, as Johnny Storm and his father Dr. Franklin Storm are African-American.
4. Normally quite light-hearted, this Fantastic Four is looking dark and sombre.
5. This may actually a bonafide Sci-fi film.