Might think it's hard to beat the final boss, huh? It's actually easy if you do the right things. Use a Pulse Rifle and wail away on Nicole. Don't pay any mind to the small black Necromorphs crowding around you unless you're completely surrounded. Then use a Force Gun to get them off. Never let Nicole near you either, or it's game over. Just keep firing off as many rounds as you can, as fast as you can at both Nicole, then the Marker when it's open and exposed, and you should win easily.
Added by: Forgoten_Scars Feb 27th 2011, ID#7061