Charles Onyett of IGN is in Korea right now liveblogging the Starcraft 2 announcement. Here's what I've pulled out of his hurried updates so far.
- Game is playable (pray for a demo at Blizzcon), but nothing is final.
- Protoss Zealots have their psi blades and shield, along with a new charge ability. There's a new Protoss unit called an Immortal, with a shield that activates when damaged-- looks like they're already implementing Paladins then.
- A new Protoss unit called a Stalker can blink around-- Blizzard wants Protoss to quickly put an army anywhere on the map.
- Three more new Protoss units: Colossus has long legs and can move quickly, Warprey is a flying unit that does more damage the more it focuses a ray on a target, and a Pheonix can overcharge weapons, but have a cooldown afterwards.
- Zerglings can now become suicide bombs in a kind of rolling form.
- There's a physics system in the game-- destroyed units can roll down ramps.
- System can handle at least 100 units at a time, and looks "similar to SC1 - both in unit and map designs." It must be 3D, though. Right?