NECRODOME

Objective 1: Activate Switch to lower outer doors. You can start by heading to the southwest to find where the crosshair is directing you. You will enter an area with some Jetpack troops and explosive barrels, its smart to destroy all of them before heading on. From there follow the crosshair as it turns a little more to the south. You should be right in front of the chamber with the first button. Since it is up higher, use your turret to hit it or if the coast is clear you can get out of your car and look up to shoot it.

Objective 2: Activate Switch to lower inner doors. A new area has just opened to the south. Exit the switch chamber and head around the left side. Begin south then head west when you hit a wall to get to the newly opened area. Be on your guard for some heavy turrets. In order to make quick work of them, but still conserve ammo, use the heavy cannon mount that can take care of them in one hit. Once you are in the new area, pickup the heavy cannon ammo and start to head easy. You will be in an area with a slope and a stream. Behind the turret post ahead of you is the switch. Hit it and take care of the jetpack troop using the laser or the heavy cannon since there is ammo nearby.

Objective 3: Retrieve Flag. Head back toward the west and the door to this area, directly across from the door is a ramp leading to the south. Go up this ramp and destroy the heavy turret that guards the flag, pick it up and your almost done.

Objective 4: Return Flag to start platform. You can always explore around but there isn't much else to find in this level. Head straight north, and once you are out of the area head to the north east, and follow the crosshair. You'll encounter a few more turrets and troops but if you aren't in the condition to fight, just speed on for the exit.