In this modpack you have to survive a zombie apocalypse. Zombies spawn on day time and, at night, I can't count how many they are. In order to survive, you can either survive normally like in vanilla, or hunt down loot blocks. Loot blocks appear in the middle of nowhere or inside structures that spawn in the world. From them, you get weapons, supplies, gear, etc. You can also build helicopters and planes to transport stuff, kill the undead and bandits or search for loot blocks.
The mod 'Mekanism' is included in this pack as well in case you want to develop an industry.