My first reaction when I heard that Marvel was making a movie about the Guardians of the Galaxy was "Why?" It has never been a popular group. Then I saw the first trailer and changed my mind. It looked much better than I expected.
To be honest, I had th same reaction when they announced the first Iron Man movie. The character had been run into the ground multiple times and I'd stopped being interested in him years before. Then I saw the trailer with Robert Downey jr and I was hooked.
I'm not sure the Guardians is as good a movie as the first Iron Man. The following year the president of the Motion Picture Academy admitted that Iron Man should have gotten a nomination for best picture. I doubt if anyone will make such an admission about the Guardians. Never the less, the movie is a whole lot of fun, right up there with Captain America, the Winter Soldier as one of the most enjoyable movies of the year.
Who would have thought it when the Guardians first came out in 1969? They only lasted one issue. Actually, they were given one-shot try-out. The team at the time was a band of aliens fighting a resistance movement in the 31st century against the lizard-like Badoon. Each member was from a race that had adapted to a harsh planet, similar to DC's Legion of Superheros. One was massively built to withstand the gravity of Jupiter, another was a crystal being from Pluto. They were joined by Vance Astro, a 1,000 year-old astronaut who had traveled to Alpha Centauri in suspended animation only to find a welcoming committee who had used faster than light drive to get there before him. Along the way Astro developed telekenesis. Astro also picked up a native companion named Yondu who could control arrows by whistling.
The group was not forgotten. A few years later Howard the Duck creator, Steve Gerber, revived the characters and managed to get them their own book. It didn't last long nor was it very good. Gerber used Astro's character as a proxy to point out all the flaws in 20th century Americans/ Astro was always wrong and Yondo, the Native American stand-in, was right by virtue of being raised close to the land (or something like that).
The team was revived again in the early 1990s as a look at te future of the Marvel Universe. It lost its preachyness and was fairy enjoyable.
Except for the character of Yondo, none of the original team made it to the movie (and Yondo was drastically changed). Instead the movie was based on a revival from the 2000s. This time the team was similar to the one in the movie and took place in the modern word instead of the far future.
The director said that the Guardians was Phase 2 of the Marvel Universe. The movie certainly lived up to that promise. Previous Marvel movies were fairly self-contained. The Avengers were all from the Lee/Kirby age. In contrast, the Guardians has characters created by dozens of people.
This article points out a few of them.
The biggest influence was Jim Starlin. He created Gamora, Drax, Thanos, and the Infinity stones. The Kree in general and Ronan in particular were Lee/Kirby creations. Kirby also created the giant alien we see destroying a planet. The Nova Corps came from the character Nova who was sort of a knock-off Green Lantern (alien soldier crashes on earth and gives his powers to a deserving human). Star Lord was another one-shot who was revived and retconned a few times. Rocket started as a throw-away character from the Hulk inspired by the Beatles song Rocky Raccoon. The Collector was an early Avengers villain. Andromeda was an Avengers villain during a period when Thanos was dead (Thanos and death have a complicated relationship).
I could go on at length and that's just what I caught from a single viewing. The movie is like Starlord's mix tape, the most awesome parts of the Marvel Universe.