If you like hardcore and hardcore mode in Minecraft is not enough for you, this mod for you. There are some changes for hard game:
1. You have infinity hunger effect, so you need more food for survival.
2. You have nausea effect if your HP lower than 5. So say "goodbye" for your mind.
3. At night you will have fear effect, which give you blindness and make you really slow. Bed is really useful here. And that works in other dimensions too.
4. In the Nether be ready to burn if there isn't snow block in both hands.
5. There is infinity rain in your world.
6. You can't choose peaceful mode. If you try, you will die.
You need to be very skillful to survive. Good luck.