Warhammer 40K Boltgun - Playthrough Part 6

At the end of a factory-like level you face the Great Unclean One - one of Nurgle's abominations. It's a giant troll-like creature, which spews acid at you, has a giant sword and a giant bell it rings when you get close enough. I found the Vengeance Launcher to be pretty effective in this fight for its strike and retreat capabilities.

The Deep Vault was a big level with many portals and after it you reach Heresy Lurks. There was an annoying section where you get killed by the falling ceiling and it took me several tries to understand what was happening. You basically have to learn where the exit is and rush there. After that you use jet-packs to jump between buildings filled to the brim with Chaos Marines. To top it all off you have to fight the Traitor Psyker at the end. His move set is pretty much the same, but the map is smaller meaning you have to constantly deal with the stronger enemies he summons. Since this is basically a survival challenge it's best to focus on the Sorcerer. The best strategy I've found is to shoot your best weapons (basically the Meltagun) at him as you approach him and then deal some damage with the chainsword. Then retreat, reload and repeat. When you defeat him he teleports away to your ship and uses the fragment to alter the Warp-drive to summon more daemons. It's your task to stop him.