Right after the announcement of their highly-awaited sequel of the original StarCraft: Broodwar Blizzard made it clear that they'll stick to their original game. There will be no 4th race as it was initially expected. No one was to interrupt in the Protoss-Zerg wars, except the intergalactic human prisoners banished from their homeland into the great Void. So we already saw the new Protoss "alliance" and the remaining Terrans, but there was not a word (or a shriek) from the Zerg.

So what do you know so far ?

Protoss - According to Captain Picard (you know, that bald guy from Star Treck) they are the major enemy of the Confederacy (call it the UED if you wish). Armed with big flying and shiny thingies, shooting lasers, they possess the valuable knowledge of teleporting, transforming/exploiting both organic and non-organic matter and some other tricks. Along with the devastating weapons the Protoss are also good conjurers. Master Yoda says, that they even mastered "the force" and will not hesitate to use it.

Terran - Big boys, love big guns. The poor earthlings struggle to survive in a world filled with giant cockroaches and UFOs. Apparently their key of success is "sex, drugs and rock 'n roll" or in other words - medics, stimpacks and the great sound produced by 10 probes blown by a Reaper mine. Let's not forget the great mechs inspired by a movie shot back in the 21st century called "Transformers"

Zerg - It is clear we don't know much, so instead of listing the 3 units we know, let's focus on those we don't know. An ex-blizzard employee, who worked for the company till some months ago managed to took some inside pictures with his cellphone of the StarCraft 2 artwork. The video begins with some pictures of Blizzard HQ (which can only prove that guy had access to the building) then proceeds with some WoW sketches of Blood Elves (never show before) followed by text, that says these pictures were taken months ago before the expansion was released. The most amazing thing is the 4 Zerg drawings of units that were never presented by Blizzard. Two of them are flyers and one other land unit that looks a bit like the creature from the "Alien" series.

Important note - shortly before this item was activated the video was deleted and it is no longer available. The opening pictures clearly state (with no doubt) they were made by an insider. And the fact that the video was removed can only mean that it was not fake. The only screenshot that remains is the one that you can see here.

From StarCraftLive.net (while the video was available)

Quote from Blizzforums' thread

Second Quote from Blizzforums' thread

So it is either someone who was afraid he may get sued, or the admins of the site decided not to take any risks. But there is almost no doubt those pictures were authentic.