Very nice game 4/5. It seems to be a little bug on mission rate, near the clock. It goes directly from "perfect" to "good", "great" is not mentioned. A suggestion: I would place a countdown instead of a clock. In this way is clear that, as example, to obtain "perfect" it is necessary to finish in 3:30. After the countdown reaches zero, the "perfect" becomes "great" and the countdown is set, let say, 2:30 and so on.