The mode, a feature in Obsidian’s Fallout: New Vegas as “Hardcore Mode”, brings a new challenge into the Fallout 4 experience.
With survival mode in New Vegas, the game became more realistic. Rather than being able to guzzle Rad-Away and expect the radiation to go away all at once, it would go away gradually.
Your thousands and thousands of rounds of ammunition would now be weighing you down just like the armor and weapons you pick up, and the Courier needed to eat, drink, and sleep periodically. Companions could also permanently die.
The Fallout 4 Survival Mode, according to Bethesda, was inspired by Dark Souls and is built around four different pillars: resource management, intensified combat strategy, slower exploration, and increased realism.
For instance: You can no longer save just before risky encounters. Now you can only save while sleeping, and autosaves are extremely rare, rather than happening whenever you enter a new location. The fast travel system is disabled, forcing you to hoof it everywhere.
Combat also now carries a big risk, as enemies no longer appear on the Pip-Boy radar and also hit harder, though an Adrenaline system will also help you hit harder as well.
Like New Vegas, players of the Fallout 4 Survival Mode will also need to eat, drink, and sleep periodically. If you don’t, you’ll have decreased action points due to your character becoming fatigued.
Unlike the vanilla Fallout 4, you also can’t just expect to hop on a mattress in the middle of nowhere and expect to wake up refreshed. Now the type of bed matters as well, and can effect your quality of sleep, your immune system, what diseases you might catch, your limbs healing, and how much weight you can carry. Stimpacks and ammunition also all have weight.
If you’ve been looking for a more challenging Fallout 4 experience, this mode will definitely be for you.