It figures that right after I write my hands-on preview of XCOM: Enemy Within, Firaxis would then release the video of its PAX closed-doors demonstration. (Video during my playthrough was forbidden.) Well, it's worth the double-dip, because you can see some things I forgot to mention.
The first is that a MEC trooper -- the hulking mechasoldier who debuts in Enemy Within -- can just shoot away cover with something called collateral damage. Whoopsie! That's kind of a big talent. Problem is, the MEC empties his ammo in doing so.
The second is the needle grenade, which has a higher blast radius but also obeys cover, so if you can angle it so that one of your soldiers is behind cover in the blast zone, but the baddies are not, then you get the benefit of tossing explosives without hurting your own folks. However, you can also do extremely dumb things like toss a needle grenade in the area of a bleeding-out teammate, as I did. That's probably why I didn't mention this yesterday. Also note the scan lines that appear over a target when it'll take damage from the blast radius. Ananda Gupta (the lead designer and narrator of this video) said that detail was added at the request of players.
The neural feedback talent for gene-mod soldiers also is on display here. And some good old-fashioned teamwork on that Berserker Muton, setting him up for a two-hit kill; that is, the MEC hits him and the Berserker hits the pavement. Firaxis says it has more to announce for XCOM: Enemy Within before the expansion's November 12 release.