Some interesting details I noticed...
1-If you look closely during the Walker scenes, you can see smaller walkers which more closely resemble the classic AT-ATs, although with what looks like a few cosmetic changes.
2-Likewise, during the big Imperial gathering in the hanger, you can see AT-ST style walkers around the place.
3-Curiously no signs of the Casino planet, Rose, or Holdo.
4-The shot of Kylo looking into the hanger looks a lot like the various scenes of Vader looking out star destroyers in the OT (Although Kylo did this himself in TFA).
5-Also, we now know why Kylo's shattered mask was smoking-he smashed it into a light.