The following is taken from the ET:QW official Community forum:
Game will ship with:
* Multicore CPU support
* Will run with Vista
* Widescreen support
* Ranked and unranked server ability
* Ingame demo recording
* VoIP will be included in game
* World builder will be released after launch as an SDK
* DVD Support only
* GDF and Strogg can not drive one anotherís vehicles
* Maps will have chained events so you cant take a flying apparatus and finish the map early
* Deployables don't get destroyed when you're killed, only when you change class (or someone else is unkind and shoots it/blows it up).
* You can't shoot off the Tormentor's repulsor arrays in the same way you can shoot wheels off GDF vehicles.
* Map objectives can not be retaken, Forward spawn points can.
* There will be melee weapons but no punching or kicking
* Air units will be able to fire counter measures to avoid rockets
* vehicles have a first and theird person view
* Punkbuster is the anti cheat client