Regardless of your progression through the main game, you'll be facing the entire Reaper ground force roster here. Put light emphasis on stripping shields, medium emphasis on crowd control, and heavy emphasis on stripping armor and causing fire and biotic explosions. There are also several points in this mission where you may find yourself fighting enemies from multiple directions at once. If you train your Shepard with Energy Drain or Defense Matrix, you will be able to restore a downed shield quickly.