Guardians of the Galaxy is a gorgeous and wonderfully entertaining space opera. The characters are so damn lovable, the world building is incredible, the soundtrack gives the film an entirely unique feel, and the effects are astoundingly first rate.
The story follows the pattern of the space fantasies that influenced George Lucas, but the presentation is the work of the extraordinarily gifted filmmaker James Gunn. If we ever forget that the MCU was ever a thing (we won't but let's just be hypothetical), many generations will still be talking about this fantastic movie.