For each level you can get up to m*m points, where m is the minimum number of moves.
The score you get for particular level is proportional to
1 / ln(1 + x/m),
where x is your number of moves plus penalties.
x = moves + hints + 0.25*total_hints + 0.000001*total_seconds
moves: number of moves in your best solution for this level
hints: number of hints you used during your best solution of this level
total_hints: number of hints you used for this level since the beginning of the universe
total_seconds: number of seconds you spent playing this level