Warning: Due to the nature of these videos, be advised that there are spoilers. View at your own discretion!
Sum Gai's Trailer and Review:
Sum Gai's put together a kick-ass trailer for AAG. He also did a video review sometime back.
Missileboater's Guide Videos:
Missileboater's been putting together several videos showing the locations of all the shards in the game. He's also putting together videos of each of the boss battles.
ARPerson9's Game-Breaker Videos:
ARPerson9's more about taking the game's battle system beyond it's limits with rather interesting results.
Let's Play Videos:
Here are Let's Play videos of AAG with commentary from various awesome individuals.