Being played by the devs.
edit: crap, it's just about to end - ah well, I tried :p
Played for me.
Comment on Eldar -Wraithguards look scary, D-Cannon spamming bastards. Basically they are fairly slow, utterly useless in melee, carve up vehicles and infantry that stands still. They suck at hitting moving targets so melee is especially good at them. Their tendency to miss moving targets does not apply to vehicles so much, though, they seem to have tore up Chaos Preds on the move on problem.
-Webway gates now infiltrate themselves and nearby units. Damn, nice. (via Croax)
Looks like Tank dominance is being toned down with all the AV on the field.
Comment on Chaos -Chaos anti-melee is like SM, reliant on abilities (Sorceror seems set here, with teleporting allied Havocs, Doombolt supporting Grenade Barrage). Notably, Doombolt/Barrage combo was used to stave off banshees. ==--> Grenade barrage fires with a delay, seems to function like a longer range but less reliable Scout Shotgun Explosive Shell. Looks like Chaos anti-melee game is very similiar to SM - reliant on Havocs and knockdown abilities, as well as heroes.
-Chaos Mark Upgrades force units to stop moving, they can retreat while upgrading, but it cancels upgrade.
-Chaos Dreadnought seems like a beast with that Autocannon. And the Autocannon firing FX is pure win.
-Bloodletters are basically teleporting Banshees, more expensive (maybe more fragile, not sure).
-Empyreal Abyss seems awesome. A bit like Tyraniform, a huge building in the middle that deals the damage, and it shoots out chains periodically to pull units into the center column thing. Kills smaller units, but heroes like Hive Tyrant can take a few hits.
-Overall, combined with information on Chaos Lord and Plague Marine, Chaos heroes are the Chaos answer to melee in tier 1. They got anti-range covered well, but look vulnerable to suppression (no true hard counter to it, lots of soft counters though).
Comment on Sorcerer -Sorcerer seems to have a teleport ability that works on both allies and enemies. Not sure how it works, but it seems to create 2 small areas which swap whatever units are in them between them. Seems ridiculously versatile. -Chains of Torment back, works like Entangle, but summons a little thingmajick with health that needs to be destroyed to dispell Entangle. It loses HP gradually. Retreatable from. -Sorc has a spell that makes target units explode if they die under it's effect. -He has a sword that gives him an AoE flame attack. -Chaos Doombolt works with some delay, basically it's a Cyclone Barrage mini in every way. Direct hits on clustered targets took down Guardian and Banshee Squads almost half HP. Costs 50 energy, cooldown seems low (he fired it almost every engagement), and the Consume ability basically trades a Cultist for 50 energy.
-Sorcerer seems beastly, similar to Farseer in melee, with more offensive spells. Ton of AoE damage between his Fire Global and abilities. His portal based Teleport ability looks wicked good/versataile (I pity suppression teams have to deal with Sorc).
-GUO abilities do not seem to have a telegraphing graphic. Good news for Avatar?
-They showed of Foot of Gork. Basically a huge explosion that leaves a foot print.
Notable non-Chaos related gameplay changes:
1. All Walker power cost ramped, but so has their HP. 2. All Artillery units now seem to target ground, not units - I.E. if you order one to fire, and a unit moves, the projectile will target where they were (aka D-Cannons will now miss moving units).
QA stuff: 1. Ravener's Corrosive Devourer nerfed. 2. FC's Storm Shield improved (gives 20% ranged damage reduction passive to himself). 3. Some heroes got new abilities/wargears (like Meltagun). Mekboy's Waaagh Banner does a "Megarumbler type effect," whatever that means. 4. Matchmaking "improved," TS will "fluctuate more this time." 5. Question on specialty CSM, but we already know that Plague Marines are in and nothing else. 6. World Bearers and Thousand Sons and Black Legion are a preset skin. (I think this means color scheme, not straight out skins). 7. Teleport ability for Sorc explained - you select the location for one of the teleport circles, the other spawns automatically next to the Sorc. Vehicles cannot enter. 8. Tyranids still can't garrison except for TG. Buildings generally "improved," so they are no longer death traps. Eldar platforms can now garrison buildings. 9. Tacs now have a special ability that give their bolter fire a damage boost against Heavy Armor to help them deal with Chaos Tacs. 10. Built Demons DO NOT lose energy like summoned demons.