This one isn't that bad, but the whole "First Order=Nazis" thing kind of missed the mark. I get that nothing screams "they're the bad guys" more than a good old-fashioned 'sieg heil' but it's weird to summon that kind of imagery without really doing anything else to highlight its significance. This is the same issue from the first trilogy. Without aesthetic clues, who knows which side is actually in the wrong in this conflict? The empire never shows its hand as explicitly evil until it obliterates countless civilians with a scarily overpowered weapon of mass destruction, which if we're going to be technical about it was America's winning strategy in WWII. What I'm trying to say is I'd have actually preferred a big goofy stromtrooper U.S.O. show with giant-mascot versions of Darth Vader and The Emperor doing cartwheels accompanied by Katy Perry and a drugged out Max Rebo Band. THAT would have been way more intimidating.
Once Starkiller Base (aka Death Star pt.3: Bigger and Blaster) finally lets 'er rip, the first target is the seat of the New Republic located on Coruscant/Chandrilla along with a bunch of scrub planetoids full of nobodies. This means that the entire democratically elected government that Leia had worked towards her entire life was wiped off the map. Everybody watches as an untold number of her friends, war buddies, co-workers and family members are vaporized in an instant. Yet throughout the rest of the movie nobody takes a second to recognize that THIS IS THE SECOND TIME THAT'S HAPPENED TO HER. Has any other character in fiction experienced loss at such a comically huge scale? It's insane. At no point does anyone acknowledge this or take a moment to reflect on how one character can withstand so much death. They do give Leia a moment of force-sensitive wibbly-wobblies when her baby daddy bites it, so you'd think she'd also feel it when a few BAZILLION voices "cried out in terror, then were suddenly silenced".
The very idea of "infiltrating" a planet-sized base is silly once you realize the scale of it. The "thermal oscillator mcguffin" and the "interrogation chamber" could have feasibly been entire continents apart from each other. The fact that anybody got anywhere is ludicrous, unless the whole base was actually the size of normal human military base and the rest of the planet was just scattered with several thousand miles worth of LEDs just to look badass. Bonus points to J.J. Abrams for the brilliant idea of setting the finale at a winter/forest/battle station planet, thus getting nostalgia points for the Death Star, Hoth, and Endor all at the same time.