I love the concept too, though it has space to improve.
I found the controls a bit tricky. In the last level I jumped quite often accidentally into the water. Also a few times the light did not kill the ghosts, instead they got me, which feels like a bug. The high ghost spawn rate in the last level was also a bit annoying, but ok, as it is intended to add some difficulty.
Otherwise the delay / wait time until I got the light in was a bit too long, which resulted in pressing q a bit too often in a short time, resulting in additional unwanted deaths, accidentally turning the light off again.
It was fun, but if would have been much more fun if the issues weren't there.