Related
Effect
Determines level (each 1,000 experience adds 1 level)
Starting Value
0
Maximum Value
9999
Effect
Used to buy spells
Starting Value
0
Maximum Value
99999
You gain Experience by killing Monsters, and you can also gain a nice chunk (3,000, to be exact) for rescuing a Princess. Experience is used (in addition to Gold) to buy Spells, but beyond that I'm not sure it has any game impact. There are a number of ways to get ridiculous amounts of Experience, including killing a King (which is worth 10,000) and going into space (each enemy vessel seems to be worth around 3,000).
Effect
Determines level (each 100 experience = 1 level)