Upon clearing a room, you’ll be graded based on three things:
* Time - The time it took to defeat all enemies in the room/area
* Damage - How much damage you took when clearing the room
* Combo - The number of combo hits you landed when clearing the room.
Room evaluations are averaged at the end of the level, which will determine the number of chests you’ll get. There are also Achievements tied to the average score you get for the entire playthrough.