The battle continues...
Why it is hard sci-fi
Soft. The films science floor is the asteroid field sequence and the Hoth ground combat, both of which lean on cinematic over physical logic. The hyperdrive failure subplot is the films one engineering thread played straight, with a recurring repair effort that fails on schedule.
Science inside it
Hyperdrive maintenance under combat damage, asteroid-belt density treated as much higher than any real belt, and a tauntaun-based cold-environment expedition that treats the local biology as adapted to extreme cold. None of it is rigorous, and the film does not pretend it is.