I get to the screen where I need to defend the trenches from the enemy. It tells me to use the canon overlooking the field and the trenches but I blow up everything I possibly can and still it tells me, " you failed to defend the trenches" and makes me start over by using the canon. I'm totally stuck right at this point, no idea how to get past here, and if I don't get past here, the disc will make a nice mini frizbee and so will anything else that says UBISOFT on it. The game is kinda fun so I would really like to move on to the next screeen. How do I complete this screen? Thanks all.