Tirado do forum crymod que por sua vez tirou do IGN.
http://www.crymod.com/thread.php?threadid=32019
And the best news is that even though Warhead is a full game, IGN has confirmed that it's going to have the price of an expansion pack. At E3, EA will reveal that Crysis Warhead will retail at $29.99. For that, you'll get a campaign that is, what we're told, slightly shorter than that of Crysis (your mileage may vary since you can spend a lot of time sneaking or exploring), as well as a multiplayer suite, though Crytek hasn't revealed any details or features regarding it. Crysis Warhead is scheduled to ship later this year.
Traduzindo as partes em negrito: O jogo não será uma expansão, mas terá o preço de uma (U$29,99). E foi dito ao IGN que Warhead seria um pouco mais curto que Crysis.