-While in the final Boss level, do not move anywhere at the start. Instead, activate your jetpack and fly straightly up as high as possible. You will see a blimp that has "Duf beer" written on its side. Shoot the blimp with your RPG or Devastator and a hugeamount of items that include medipacks and ammo will fall out.
-If you have a jet pack, fly up and destroy the beer blimp. Guns and health will scatter on the ground, allowing the last Boss to be killed easier. Note: One of the best weapons to use against it is the Devastater.