Alright, start with positives:
Prequels basically don't exist
Aesthetically about as good as could be hoped for
Generally good acting
Humour was overboard but occasionally funny
Kylo Ren for the first half was great
Fight choreography was solid
Focus on emotion of combatants (well, at least compared to prequels)
But negatives:
OK, I'm sorry, but WHAT THE FUCK IS HAPPENING? What happened after Endor? Who are these First Order guys? Are they a legit government? How powerful are they? Where do they control? What's going on with the Republic? Where's their military? What is the Resistance? What's the relative strength of the factions and how do they relate to each other? Did the Republic actually sign a treaty with the First Order or something? Yeah, no doubt it's all explained in the books, great,
but I went in to watch a film. And no, comparing it to the originals is totally off: in the originals, we knew there was an evil Empire that, after 1,000 generations of peace, had taken control of the entire galaxy and are looking to crush the extremely hard pressed Rebellion who are fighting against them with almost no resources or hope of success. Simple, to the point, all makes sense, gives you a scale of the battle, explains the stakes. Fantastic. In TFA, you have no idea what's being fought for, the relative strength of any party, or anything like that.
Further, it's made even worse by being a sequel. There have already been three films (OK, six - whatever

), we already have a connection to the world. Is this supposed to be a reboot? No? Then continue the story, don't just utterly detach it. Plotwise, there is almost nothing to connect it to the originals. It just happens to be set in the same universe. With a couple of name changes it could be set 10,000 years further on. Oh, except for cameos from a couple characters and, of course, Han Solo...
Except Han Solo isn't Han Solo. By that I mean, he's the Han Solo Luke first meets in Mos Eisley. He's a recycled character, not a continuation. His entire character arc we loved him for has been erased. And it happened off screen. Because apparently that's really satisfying? But don't worry, he'll retake that character journey in two lines in the middle of the film, so that's OK then. WHAT?
Holy shit, how fucking cool is Kylo Ren! What an utter badass! Yeah, bitch be crazy! Stops blaster shots, can just switch people off! Ah, and he's got some character, OK, cool, cool, I'm digging this. And then and then and then. . .a fucking cleaner can duel him? WHAT? Absolutely destroys him as a character. I'm sorry, but all the excuses in the world (he was upset, he was toying with his meat, he was injured) don't make it remotely acceptable that the total badass we saw at the start of the film, the guy who can just look at people to make them unconscious (y'know, something
nobody else can do), gets injured by a FUCKING STORMTROOPER in a lightsaber duel.
And
then he fights Rey and actually somehow
loses to someone who's never turned on a lightsaber before? Why did Luke "Last Great Hope" Skywalker take years to learn skills Rey just has? Now, sure, you could argue this is hinting that she's been trained in the past. She's Luke's daughter! Or maybe she's Force Jesus 2.0: The Even Chosener One. OK, fine theories, could well be. But the point is that the audience has entirely lost faith in the film at this point because of Finn's ability to even consider contesting Kylo Ren: we simply can't trust the director to represent any consistency in how fights work out, so for all we know Rey winning could simply be a stupid plot hole and betrayal of the originals. The mystery should be: Wow, how did Rey fight Kylo? What's her story? Was Kylo utterly devastated by the loss of his father and unable to use the Force? What's the explanation there? Instead, the mystery is: What the fuck just happened? We don't trust the reason behind this inexplicable occurrence to be plot consistent at all, and so we assume it's a fuck up.
This is not a good response to engender in your audience to the key fight. This is not what a director should be trying to achieve. Death Star 3? Really?
I'll stop there. There were plenty of other gripes (Phasma, monster dragging Finn around, hyperspace jump to a planet's atmosphere, etc.) but many were minor and I really don't want to focus on the negatives (though they tend to require more words to express). It's only been a day since I watched it, I'm still not sure how I feel. There were definite positives! There was a focus on likeable characters rather than fifteen billion lasers. There were actual sets. It felt real. These are good things. I actually had some fun, I laughed a couple times. But I just felt lost for much of the film. Hopefully it'll work better in a rewatch, and maybe VIII and IX will improve it too. Hopefully.