a Question

NickLim27 said:
It may be difficult to understand what happened as it made a lot of references to Char's Counterattack. To understand Char's Counterattack, you would need to watch all the prequels.

I would suggest you at least watch:
1. Gundam 0079
2. Gundam Zeta (the remake movies are fine too)
3. Gundam Char's Counterattack
4. Gundam Origin

Please DO NOT watch it chronologically as what others said. Follow the released order would give you the best experience in Gundam Universal Century.

You can always watch the other side stories like ZZ, War in the Pocket, F91, Stardust Memories, 08th MS Team, & Thunderbolt some other days.

If you want to take a shortcut (not recommended), at least watch Zeta remake movies & Char's Counterattack movie.

Surprisingly, it made so less of references to Gundam Unicorn.

EDIT: It is important to build the foundation and love for Char Aznable in order to appreciate this movie.
EDIT 2: Take this as a historical journey in your life. Don't rush to watch this movie. If you watch this without understanding the history, this is a 6-7/10 good movie. However, when you have a solid foundation of prequels, it add points for the experience and turns this movie into a solid 8-9/10 enjoyment.

Hope that helps!