Shacknews posted some more collected Half-Life 2 info not all necessarily true.

• ALL objects in the game world are affected by the physics


• Movement speed of HL will be retained
  Drivable vehicles in both single and multiplayer


• Engine technology scales based on your system specs


• Known locations: City17 in east Europe, a harbor, a jail, the suburbs, a dried up ocean, an icebreaker (large ship)


• Multiplayer is important and multiple game modes will be supported


• The editor is called 'Hammer' and will be included, sounds like a complete development environment for maps, modsetc


• TF2 will be using the HL2 engine, once they decided to use the HL2 engine they stopped giving information as they didn't want to blow anything relating toit


• TF2 will 'arrive soon'.