How to Kill the Hive Mind in Dead Space

Be aware before the Final boss in chapter 12 there is a store, Upgrade Bench, and Save Station. Do not be cheap when buying med packs, ammo, and power nodes. If you are trying to get the "One Gun" achievement/trophy make sure that it is fully upgraded and fill your inventory with ammo and medium medical packs.

Leave the room, you will be at the start of the level. Before charging out into the middle of the dock, use kinesis to get the boxes. When you are ready, head towards the ship. A sequence will start, showing the Hive Mind and his tentacles.

Wait till the fight commences, take note of the yellow bulbs around it's mouth. Remember what those did to exploders and drag tentacles? If you aren't using the plasma cutter, try using a maxed out pulse rifle. Until you can get a clear shot, evade it's tentacles by strafing left and right. When it comes in to howl, open fire on one of it's yellow bulbs. If you can, try spreading the damage out on all of the bulbs without destroying them, this helps later on.

Wait till you have destroyed 2 bulbs. The Hive Mind will pick you up so you will be dangling upside down. No you have to aim and fire with your aiming inverted. This is when spreading the damage around comes in handy.

Wait for the stomach bulbs open. When you have destroyed its face bulbs, it's stomach bulbs will open up. The Hive Mind may now start shooting Pregnants after you. Be careful! The Hive Minds tentacles will destroy the Pregnants causing them to deploy.