Easy way to get Tommy gun
Go to the single mission because you normally choose from three weapons (rapid fire ones) but go and select any level (be the U.S.) Kill one on the other team then die somehow. Then when you go to campaign you should see a Tommy gun. Don't switch the guns because the Tommy gun won't be there then you will have to do all of this over again.
When playing any level with traps, constantly keep half of your view on the ground so you can see the little half invisible ropes.
Oh and sometimes it helps to follow your point man no matter how slow he is.
Outpost Mission Hint
If you are having trouble on the "Outpost" mission because you don't have any time after the 2nd radio transmission (the first being the one at beginning of mission), don't answer the 2nd transmission until after you kill all 3 mortar teams. Then answer your radio and proceed to the outpost (follow the dirt path where the 3rd mortar team is).
When you are in career mode, sometimes you'll be invited to a tournament. If you lose, turn off the X-BOX and turn it on again. The tournament invitation will come up again and you can give it another shot.