valuable artifacts.

Your final mission in Doom 3, Primary Excavation: Artifact Dig. Learn how to defeat the Cyberdemon and seal the Hell portal with this walkthrough.

Alright, you've made it to the very end, the Primary Excavation: Artifact Dig. Malcolm Betruger's got a few choice words for you as you descend. Once you're down, stock up! There are tons of weapons, armor, medkits, and ammo scattered around, but only one BFG Cell right off the bat. Grab it and any other supplies you can find. Before you head down the stairs to your left, check the pile of rock debris to your right. Climb up it, turn left, and you'll find another hidden BFG Cell. Now, head down those stairs. You'll enter the Hero Chamber. You'll see some stone tablets, a laptop showing info on them (same video you might have grabbed last level), a big sarcophagus, and behind it, a backpack with more ammo and another BFG Cell. Grab the backpack, and watch out – the wall behind it opens up, leading you further into Hell. You'll hear the Cyberdemon roaring; it's time. Follow the path, and another wall will open, revealing a platform. Step on it, and it'll take you down while Betruger laughs. You'll end up in a small labyrinth. Navigate this maze until you reach two paths. The left one is lined with red walls. Take it, and you'll find a secret Easter Egg: a brick with the id Software logo. Press it, and a nearby room opens, revealing a PDA from the id Software team, thanking you for playing. Now, take the other path. A cutscene will play, and the Cyberdemon will introduce itself. It's time for the big fight. If your Soul Cube is charged, use it immediately. If not, back away fast. Your main goal is to keep your distance; the Cyberdemon can instantly kill you by trampling you. Don't waste ammo on it – not even your BFG 9000 will hurt it. You *must* use the Soul Cube. The Cyberdemon is only vulnerable to its attacks. Imps and Maggots will keep spawning around the Hell Hole, so focus on killing them to charge your Soul Cube. When it's ready, aim at the Cyberdemon and unleash it. Remember to keep moving and stay far away unless your Soul Cube is charged. The Hell Hole gives you unlimited stamina, so sprint constantly. After you've hit the Cyberdemon with the Soul Cube four times, it will fall, and the game will end. Congratulations!