This modpack adds many things to make survival more complex, while avoiding too much complexity.
These features includes :

Better Combat and Age of Weapons add more weapons types, and a more complex way to craft them, while the Black Powder Weapons / Guns mod adds muskets and pistols.
An overhaul of world generation, with Biomes O' Plenty, Regions Unexplored and River Redux
More realistic trees, from Dynamic Trees (note that as soon as the mod making Dynamic Trees and the others world generation overhaul mods compatible comes out, I will add it. In the meantime, I recommend to deactivate them).
The addition of Dynamic Lights make the light system more realistic
Seasons are added, as well as a temperature and thirst bar, from respectively Serene Seasons and Tough as Nails
JourneyMap is added, providing a minimap. May cause lag sometimes.
Better and more realistic farming with Farmer's Delight
89 new mobs coming from Alex's Mobs
Backpacks are added
Sleeping bags are added
With the Carry On mod, you can pick up a chest as a whole, while keeping the items inside it
New ways to travel, with the Small Ships mod and the Immersive Aircraft mod

Planetonium