Some points I noticed:
McCree's right mouse button does a metric fuckton of damage. Like, a lot. At one point he one-shotted Tracer with it from medium range.
There are more stairs and pathways to vertical areas than I thought.
All of Zarya's abilities are incredibly bright and distracting. Maybe this was exacerbated by the fact that King's Row is a nighttime map, or the fact that the footage was filmed offscreen.
On a related note, the glowing orb in Zarya's particle cannon makes it very difficult to see her ammo counter and cooldowns.
"Critical hits" are listed in the end-game scoreboard. Before anyone starts to panic, these are probably just headshots.
Tracer looks incredibly strong.
Zarya's damage increase when she blocks damage with either of her shields is included in her kit as a passive.
THERE IS A FOOTBALL IN THE SPAWN ROOM :D
The bit where the two Zaryas just bombard the fuck out of Widowmaker in the hotel is pretty funny.
Seems to be pretty hard to gauge the range of her particle beam. It seems to be a lot shorter than it looks.
The fact that heroes call out that they've been picked is a really nice touch. They call out when they see snipers too.
McCree walking around like a zombie while he charges his ultimate in the middle of a heated firefight is probably one of the most unintentionally hilarious things I've seen in a while.
Hanzo's sonic arrow seems to be a lot brighter and more noticeable than it needs to be.
Weapons seem to have little to no impact on the world around you -- for example, Zarya's beam just seems to glide over walls without leaving any scorch marks or anything, which I think is why the guy in the video had such trouble determining what the range was.
Bastion's tank form looks so adorable, he's like a little RC vehicle. I think I'd kinda like it to be bigger somehow, it looks kinda silly and he's super low to the ground in his first person view.
Play of the game seems like a genuinely neat feature. If I ever have a particularly nasty game, I can see myself being cheered up by an impressive play of the game clip at the end of the match. Unless I'm the one being killed, in which case fuck that :D
Every hero has unique stats tracked on the end-game scoreboard! This is pretty amazing.