I'm really glad you enjoyed it and liked the targets. The ranking was meant to allow people to finish imperfectly (great for a game jam, not every judge is going to be great at every type of game) while allowing people to try the Hitman 'ghost' runs for people who find the imperfect runs too easy. And then I screwed up the detection mechanics right before the deadline making imperfect runs much harder. Oops.
Slight spoiler: The easiest way past the final radar zone is to go up the right hallway, wait for the radars to sweep by (by doing switch backs in the hallway to wait). There are other ways past, but that is the easiest by far.