Tough as Nails aims to significantly increase the difficulty for the player in Minecraft. To start your adventure out, you’ll be given fewer hearts. In order to replenish full hearts, you’ll need to find heart containers throughout the world but until then you’ll have to survive with a deficit.
Another wrinkle in your adventure is thirst. Now along with maintaining your hunger level, you’ll need to also replenish your thirst level. This can be done by filling canteens with water or crafting various juices.
You’ll also be affected by outdoor temperature so you’ll have to act fast or it may cost you dearly. You can craft a thermometer to show you real time temps and you’ll also see an indicator in the middle of the screen depending on how cold it gets. You can build a fire and wear warmer clothing to help offset the cold.
You may also notice throughout your journey that the seasons change over time. It’s a slow process but you can also craft a season tracker to see when it changes.