Easiest way to play through is to firstly play on Easy difficulty with the Grunt Birthday Party skull on. The GBP has a radius of damage that can kill other grunts and jackals that are within range instantly, making it perfect with crowd control.
When you finish taking out the first wave or enemies after spawn, make sure to swap the assault rifle with a plasma pistol. Stick to a magnum/plasma pistol or carbine/plasma pistol combo for the rest of the run.
From that point forward, move as fast as you can and kill enemies before marines have a chance to move forward. Use the plasma overcharge to take out brute shields, then headshot them for easy kills.
Marines aren't strong on this level for whatever reason, but if you have at least one standing after the hunters on the last major wave of enemies near the end, you're golden.
Extra tip: On the last area, take out anything with an explosive or precision weapon first. The marines in this area like to take cover by themselves, and have a lesser chance of dying if you limit the enemy's combat effectiveness.