I just finished listening to the Gears of War demo that's available on Megadeth.com, and what a fucking disappointment it has been :/ I hope that it sounds so lame, weak and poppy due to it being the title track of the console game of the same name :| Or maybe the demo doesn't represent the final cut.. One can only hope.
The lyrics sound like they were written by Justis or Electra Mustaine (his kids) :S An excerpt (the chorus):
Smart bombs, precision guided armament
A more sophisticated way to end up dead