Yeah, really. I forgot about this, but I would dearly love a Skyrim hardcoe mode.
Water: You have to drink fresh water every 12 hours. Purchasing a waterskin would vastly increase this (like that trusty Vault 13 canteen you get in F:NV). Fail, and you lose stamina, then health. Death occurs in 3-4 days.
Food: You have to eat every 24 hours. Fail, and you lose stamina, then health. Death occurs in 10-15 days.
Sleep: You have to sleep every 24 hours. Fail, and you lose Magicka (loss of concentration). Insanity occurs in about a week.
Cold: Swimming in icy water depletes stamina in 30 seconds, then health in 120 more. Healing well reverse the effect.
Heat: You stand on a fire, you burn. And the effect is cumulative.
