Och, nevermind. Didn't hear the sound, because i had my headphones off. But still, I think you will benefit a lot from 3d sound instead of "2d" one. But I totally get the time restrictions and it's tough to make everything in 3 hours. And also, that's how it works in real world(first you see the light, then sound)
But anyway, with the tip of following shadow helped a bit with direction, but still, it's a lot of guessing there involved.
So my bad there haha, trying to change the speed of sound to be faster than light one :D