http://fenglee.com/game/aog/?fb_comment_id=fbc_377772355668068_1871854_388923044552999#f209c6f39
As it says, the challenge is kill them all. Highest score with the lowest time to kill all titans win! Step up and prove the Mikasa is strong in you!!!
As you can see, I'm a mere cannon fodder leaving 16 out of 32 titans. So, anyone else can do better?