Detail wise? Prosthetics.....The bad part about the character design in Gears of War is that the characters are EXTREMELY bulky, like cartoon character on steroids bulky....So now that I think about it, CGI would probably be the best choice when it comes to accuracy....But obviously the movie could go either way, live action or CG.... And really the only way they'd be able to do the Brumaks(The big locust) would be to use CG, except for close up of certain parts like heads or feet, then they'd probably use puppets.