I’ve stepped through the video frame-by-frame and came up with the following observations:

• 00:13 – 00:15 From the Loadouts bit, I think it’s clear that jetpacks, active camo, and sprint are all armour abilities.
• Also looks like the radar shows you the name of the area you’re in e.g. “Slipway” (00:15) , “Yard” (00:21) – should help with team communication
• 00:22 The bit where the Spartan survives the Ghost ram, looks to me like the Spartan does some kind of power punch to the ground or something that kills the Ghost? As kidtsunami points out on the HBO Forum the movement of the Spartan is very reminiscent of the action in the Halo 3 CGI trailer where Master Chief triggers the bubble shield
• The Covenant weapon at 00:48 looks like a plasma grenade launcher or rocket launcher with tracking projectiles
• Human grenade launcher at 1:03.
• You can see the armour ability icon “recharging” the jetpack ability at 1:05 – a small circle around the icon.
• 1:09/1:10 some kind of new gametype where you have to blow up the generators? It’s marked with a “C”, and it’s definitely called a “Generator” in the text that comes up when you blow it up. A Territories variant?
• 1:12/1:13 – Phantom airstrike taking out the tank?
• 1:16 is definitely some kind of Covenant equivalent of the Spartan Laser.
• 1:17 you can see “Revenge” come up as he headshots the guy – is this a new medal?
• 1:20 – DMR looks like one head shot kills.
• Looks like the Covenant Laser is back at 1:23 (top-left, targeting the tank).
• 1:24 Guy that lands beside the “May 3, 2010″ shoots the human grenade launcher towards the camera

Conversation about the video is progressing in this thread on the HBO Forums