Nice little game with a happy ghost.
The game really needs some sound effects for when you are "booing" and getting damaged by lights.
I do like the different "boo" graphics that appear though. And I think I saw the the humans shaking a little bit, I saw the light slightly shaking side to side, it would be good if that effect was more pronounced.
They just disappear when you scare them too much, is that meant to happen?
Overall good work, you could do a lot more with this idea and it would be interesting to see what you come up with.