Harder Hardcore makes you start the game with one heart only. The way to get more hearts is pretty hard! There is a small chance that a heart will drop from a mob you kill, which later on you have to combine with a container, and right-click on yourself.
Mod can be used in both survival and hardcore, but was designed mainly to make your hardcore world even harder!
You can get more hearts than original 10, however you start with only 1!
Hope you enjoy this small, hardcore expanding mod!