I've seen a couple of Gundam films before, but this franchise is so overwhelmingly extensive that it's impossible for a non-fan to be entirely up-to-date. I recognized a couple of names and characters, other than that I experienced this film as just another story set in the broader Gundam universe. In that sense, it wasn't all that difficult to follow.
This film tells the story of Hathaway Noa, who joins a terrorist organization called Mafti. They want everyone on Earth to leave the planet, and support is slowly growing for their organization. When Noa bumps into an enemy officer and a mysterious woman, his outlook slowly starts to change.
The art style is a little odd (very detailed, still the characters look a bit plain), the animation looks slick in places, a bit pedestrian in others. The story is simple, and the politics weren't too interesting for someone not embedded into the Gundam world, but once the mecha actions picks up, that part of the film is quickly forgotten. Pretty decent.