The first mission isn’t really a challenge but I wanted to include it for completeness.
Killing the Husks
The first enemies you will run into are a few husks climbing a wall. You are supposed to use weapons and it seems as though the mission doesn’t continues until you do. Once Anderson says that he is out of thermal clips and jumps down you can follow him. There are some more husks to take down. I used throw to kill them and used a heavy melee to kill the last.
Killing the Cannibals
After the long cut scene and some more walking you get to killing com cannibals. I again used throw to kill all of them. You can use the pull throw combination (you have to use pull first) to set off biotic explosions. In fact that is the primary way that I usually kill enemies.
Be sure to stay behind cover. After you have killed these cannibals you move on. There are some more cannibals to kill, you can use the same techniques but be sure to find good cover, as before until you get to the radio. After the cut scene you have to wait for a while before the Normandy comes and picks you up. Be sure to focus on the cannibals that spawn near you and use the pull throw combination on them first. Once the Normandy comes in and shoots some missiles you are done. This fight is time dependent so it doesn’t matter how many enemies you kill as long as you stay alive.