Add agility, health and hunger.

[slemonide]

Hunger would slowly grow. Agility would decrease as the player walks and as hunger grows. Health is decreased if the hunger level goes too hight. Player also gets slower as agility goes down.
Player should be able to each cave plants and cave rats to decrease hunger.
Monsters and traps (to be added later) should also decrease health.

If health gets too low, player dies and the game is lost.