The Broken World Update

Something got out of a laboratory and it has been winning ever since.

Fungal Infection: Spore is the heart of this pack. Everything else — every cog, every reactor, every cannon — exists because of it.

The infection

It is not a mob spawner. It is an opponent.

It evolves. One kill starts an infected mob's evolution timer. Seven kills starts hyper-evolution. An Infected Human that survives long enough becomes a Knight, a Griefer, or a Braiomil. Infected Pillagers become Howlers, Stalkers and Brutes. The longer you let it feed, the worse the thing that comes back.
It takes you with it. Die, and an Infected Player spawns carrying your name into the world. Your own corpse becomes part of the problem.
It rewrites the map. Stone, dirt, deepslate, sand, gravel, netherrack, soul sand, even end stone all have infested counterparts. Grass becomes mycelium. Territory you lose stays lost until you take it back.
It builds. Proto Hiveminds chunkload their own position, wall themselves in flesh, spread madness through nearby players, and dispatch Vigils to raid. Let three of them establish and the world itself changes state.
It calls in artillery. Wombs bank biomass until they can summon a Calamity — a 500 HP Howitzer, a 450 HP Leviathan in open water, a Hohlfresser tunnelling underneath you, or a Hindenburg carrying a radius-16 nuke. They break blocks. Your walls are a suggestion.
It sounds like it. Spore's music system replaces the vanilla soundtrack. Put headphones on.

The counterplay

The infection has real weaknesses, and the entire industrial half of this pack is aimed at them.

Cold kills it. Infected are weak to cold and will not spawn in cold biomes or the deep dark. A base in the snow is a defensible base.
The Cryogenic Decontamination Unit cleans infested blocks back to their originals in a 20-block radius and lays down snow while it works. Reclaiming ground is a machine problem, which means it's a Create problem.
It starves. Cut the infection off from food and remains and it weakens on its own.
Its corpses arm you. Mutated fiber, armor fragments, claws, tumors and cerebra build Living, Plated and Flesh exoskeletons, plus spears, cleavers, scythes, syringe guns and living weapons like the Bile Blaster and Acidic Assassin.

The arsenal

Create, plus most of the ecosystem — Aeronautics for airships, Big Cannons with Advanced Technologies and Enhanced Shells, The Factory Must Grow, New Age, Deep Seas, Power Grid, Hypertubes, Armored Constructs, Gunsmithing, Copycats+ and more.
Mekanism in full, with Generators, Tools, Turrets & Fences and More Processing.
Immersive Engineering for the middle path.
Superb Warfare and TACZ for firearms, Simple Planes and Immersive Aircraft for when the ground stops being an option.

Airships are not a novelty here. Everything below you is infested.

Everything else

Terrain runs on Tectonic. Underground Bunkers and Lootr give you somewhere to scavenge. Farmer's Delight and a full kitchen stack — Create: Central Kitchen, Create: Food, Create: Winery, Brewin' and Chewin', plus Ocean's, Veggies, Fruits, Pizza and Pineapple Delight — because the infection starves and you shouldn't. Sophisticated Backpacks & Storage, Jade, JEI, Simple Voice Chat, GraveStone with Curios compat.