What do you guys think of a GPLed commercial game release? Possible or impossible?

Shadow Warrior Source was just released GPL so yeah, it happens.

I'm not talking about source-code release game. What i mean is a commercial game like for example Battlefield Vietnam released under the GPL frm the start.

Possible. The key is dual licensing e.g. releasing the game under a commercial license as well the GPL license. MySQL AB is actually doing this with their MySQL database, which are also available under two license models.

More info on dual licensing:
http://www.linuxinsider.com/story/38172.html