Hard Mode Tweaks is a compilation of gameplay modifications, mainly around playing with natural regeneration off. A couple of the tweaks included are the ability to change the length of the minecraft day, changing game rules from the config file and the ability to heal when you eat. You can find the full list, with their respective configuration options at the TweaksList.
Curse: Hard Mode Tweaks
- Install Forge.
- Copy the "hardmodetweaks-*.jar" file to the "mods" folder.