Score
A player's score each run is determined by the following formula.
Though complex looking, the dominant factors in score are the number of rings collected and the number of turns taken.
score = (xp^.5) + 100*numRings + 10*numFloorsExplored
//1/2/4 based on difficulty
score *= difficultyMod
if game was won then
ringBonus = (numRings^2) * (50,000,000) / numTurns
//1/2/4 based on difficulty
ringBonus *= difficultyMod
score += ringBonus
