While noting that I think this was a tremendously fun movie that I expected to watch many more times in my life, there are further nuances I want to include in that evaluation — stuff I thought worked, and stuff I thought didn't (as much).
I come to this in terms of a comic geek who probably overly-respects continuity, but who, basically, figures that if it ain't broke, it should only be fixed if necessary to some greater purpose.
So I'll start positive and work my way down from there.
Rocket Raccoon – Everyone loves Rocket, and with good reason. For an angry and bitter little critter with an over-fondness for explosives and firepower, he's just plain funny. There's a scosh bit of force-feeding of his origin (a frequent flaw here), but mostly it works, from subtle glances at his back to his drunken I-don't-want-your-pity pity-me speech. In many ways, Rocket is the straight man here, reacting the way we do when Quill proposes another lame partial plan, and embodying the instinct for self-preservation as well as absolute loyalty to his bro, Groot.The trick, of course, is not to overexpose him in the future — he's a great ensemble player, but probably not so much a solo (or even duo) star.
Groot – Everyone loves Groot, too, though there was no great reason for Vin Diesel to have the role other than publicity. He suffers a bit from being used for deus ex arboria, but he's such a pure spirit (whether of anger, curiosity, or cheerfulness) that it's hard to dislike him. And, unlike everyone else, we don't go through a backstory and origin or even how he and Rocket hooked up. That he comes across more as a character than as a plot device is a tribute to the film creators.
The Ships – I wasn't fond of the designs when I first saw them in the trailers, but I have to say the various spacecraft really grew on me over time, from the Ravenger wing ships, to the Nova stars to Ronin's awesome (and morphing, and dark and scary) spaceship. The through-the-windshield shot felt a bit repetitive, but also effective.
Peter Quill – Yeah, he's Han Solo and Cap'n Jack and every other snarky, seat-of-the-pants, scruffy rogue-with-a-heart-of-gold anti-hero of the past half-century. And that's okay. He comment to the Novas at the end that he's going to watch over his murderous band — comes across as sincere and and a sign that this was an actual story that showed character development and change. The Quill at the end of the movie is not the same as the one at the beginning. He makes for a good emotional heart to the movie. There are still a few weaknesses here, though — his attraction to (and self-sacrifice for) Gamora feels a bit contrived. While his origin was cool, there was no basis for thinking that his mom gave him his "bandit name" or, much less, why. (The comic book origin isn't any better, so there's that.) Add the too-coy hinting at his paternal origin (which appears to be being set up to be different from the current comics), and it's a bit of a mess on the edge of an otherwise memorable character.
The Music – The use of the 70s mix tape was inspired, in terms of lending an air of fun and a sense of nostaligic familiary for characters and a setting that nobody here would ever recognize. It also gave Quill a bit of schtick that added to the humanity of his persona. That said, a lot of the music in the movie, vs. the trailer, was much more background, almost annoyingly so.
Knowhere – Well rendered, well explained, a nice set piece.
Drax – I was unimpressed in the trailers, but Drax in the movies was much more interesting and enjoyable, and I found his tats fascinating. Showing him being completely outclassed by Ronan was probably once too much, and it would have been nice for him to be something more than just the Really Strong Brawler Who Isn't Strong or Fast Enough vs. The Big Bad Guy. The badinage between him and Quill was okay, but I never quite got a strong sense of his character (one the one hand he's all about honor and moral condemnation, on the other he has no problems breaking the law or beating up on people who irk him).
Thanos – Thanos is the Big Bad of the Marvel Cinematic Universe. It was a gutsy move to go from "He's a mysterious figure pulling the strings behind bad stuff happening on Earth" and "In Deep Space, everyone knows and is afraid of Thanos," but, unfortunately, that's as far as it goes. Why is Thanos such a bad-ass? We don't know. People work for him, but not for reasons we understand (and by the end of the movie he's lost one "loyal" tool and two "disloyal" ones). He has a plan, presumably, but seeing more of him hasn't added any clarity to it. He sits on a big, looming, floating space throne, but there's no sense of power beyond that. Thanos, comic-book-wise, is more hands-on — he's a Vader, not a Darkseid. He's also a fascinating character, psycho-analyzed by a variety of writers, and none of that comes through here. He's a great character, and we should have seen 95% less of him than we did here, because what we saw was simpy not impressive.
Cosmo – In the comics, Cosmo is a telepathic Russian dog in a space suit. He runs a bar on Knowhere, and, eventually, the whole place, as I recall, and has hung out with the Guardians on numerous occasions. I suppose, for sake of scaling, it wasn't a bad thing to make him a Collector's item, but I'd have loved to see more of the original character (like, oh, running the bar in Knowhere that they spend time at before seeing the Collector).
Xandar and the Nova Corps – Granted there's a ton of continuity around these folk, they seem to have gone for the most boring, and in a vague way that doesn't really engage the viewer. The Nova Corps is centered on Xandar, but is it just a local planteary system, and its army, or is it really an interplanetary organzation of law-givers? Why are they writing treaties with the Kree? Why would the Kree sign? Why do they seem so weak (guys in costumes, some nice robot sentries, some generic spiky space ships, a kind of lame Tholian Web thing), and what does it mean that so much of their force has been now destroyed? And with all of that, why no indication of the actual super-heroes in the Nova Corps? I mean, I understand how that wouldn't have fit well into the story, but even a mention that they're busy somewhere else and can't get back in time would have been useful. As it is, the whole thing is sort of a lame United Federation of Planets, without the cool starships.
The Infinity Gems – Or stones. Or, as here, various bits. We've seen the Tesseract (Cosmic Cube). We've seen the Aether. Here we have a purple gem. One thing missing, both in the backstory force-fed us by the Collector and in what's been shown to date, is whether the gems themselves vary (as in the comics) in their power, or are they just Really Powerful McGuffins each in their own way? In the comics, each of the gems has power over a fundamental force — time, space, power, soul, etc. Here, they just all seem to be Very Powerful Things, sought after by Thanos (and the Collector). (One has to wonder whether the Asgardians will be back any time soon for that Aether they left in the Collector's custody).
Gamora – I love this character in the comics, raised from childhood by Thanos to be the perfect assassin, rebelling against him when his mad nihilism grew too great for her loyalty. But … I found her the weakest link of Our Heroes in this movie. Her fighting abilities are good, but not spectactular, as demonstrated by how eaily she's handled by Quill and Rocket/Groot in an early sequence. Zoe Saldana comes across as weak and whiny in too many places — the arc of her rebellion against her adoptive father is completely glazed over; she's already abandoning him when things start, but for reasons we don't really get, and her shift then into being a Guardian who actually gives a fig about Ronan and the Infinity Gem and all of that feels more contrived than organic (as does the nascent romance between her and Quill — why does this thing have to happen?). A lot of potential there, but not very fulfilled.
Yondu – So in the Comics, Yondu was one of the original set of Guardians, but there's not much left of that character here save for appearance (color and skull ridge) and power (he was a master archer whose specially crafted arrows could be controlled by his whistling). He was also, as I recall, something of a stiff. There are some neat aspects to this iteration of Yondu — the arrow bits, the surrogate fatherhood over Quill — but other aspects I found annoying. He's a superfluous mostly-bad guy, in a movie already full of them. He's tied into Quill's origin, which is already amusing. And he's kind of a redneck mob boss who grated on my nerves whenever he was on screen.
The Credit Sequences – Okay, Howard the Duck was cute (though I hope that is the end of seeing him). And, as someone who actually liked the movie, that didn't bother me. What bothered me was making it the final tag for the film. In the words of someone sitting the row behind me, "I sat here all this time for that?" The credit tags for the Marvel movies have been a combo of (a) humor and (b) foreshadowing. We got the former (twice; the Drax/Groot sequence was even more lightweight, and too long), but not the latter, which gave things a bit of a let-down for me (and worried me a bit — was there no sense of where this, or the parallel MCU, story is going? Is there a reason a bit more of Thanos, showing his plans are actually still intact, bwah-ha-ha, wouldn't have worked? Or something else to tie this into the future of the MCU? Don't they know?)
The Collector – After the setup, he came across as fairly useless, aside from giving us some exposition about the Infinity Stones and (in so doing) tying the other MCU movies into this one. Then a post-credits laugh line. How far is an Elder of the Universe fallen? Hell, the Broker was a better developed character here than the Collector, and apparently had better security, too. Bah.
Ronan and the Kree – So in the comics, the Kree are one of the big powers it the galaxy (actually, it's based in one of the Magellanic Clouds, but let's not get picky). They are a militaristic, technocratic empire, ruled over by the Supreme Intelligence, a big A.I. being that incorporates the wisdom of all their past rulers. Ronan the Accuser is one of the Kree's enforcers, fulfilling jobs too focused to send their fleets. In this movie, however, he's changed into a xenophobic fanatic, working for Thanos (sort of), rebelling against the Kree (sort of) and their namby-pamby treaty, coverd in dirt and ritualistic goo, and determined, for reasons ungiven, to destroy all Xandarian people and culture. In and of himself, that's not bad, but it's a mystery why they actually chose Ronan for that role, since its really nothing like him. Also, for a genocidal lunatic, he's very easily distracted at the hour of his triumph, and spends his last minute sort of watching the events before dying. He has his moments (in particular when thrashing Drax), but it just felt like tampering for tampering's sake.
Nebula – Yes, she is (or claims to be) the daughter of Thanos in the comics. Here, she's really just another bad guy in a movie that is swarming with them. We get very little sense of who she is except being shouty and angry and resentful of how Dad Loves You Better (in His Arch-Villainous Abusive way). In a movie about people and their bad parental experiences, Nebula fares the worse, and is a waste of Karen Gillen. But, of course, she'll be back. Unless she isn't.
A lot of complaints above, such that I reiterate that I really had a lot of fun with this movie, and none of the above takes much away from that. It keeps it from being (in my opinion) as good a movie as The Avengers, but it's mostly about things I would have liked to have seen done better, not things that were, per se, bad.
