As a way to make your levels dark it's pretty cool!

The flickering of the light (when you're not shooting) is a bit too much for my taste, I would keep
effects like this a bit more subtle.. but that's just a minor thing and my personal opinion

However, it might be a bit more flexible if you used global light for the level's brightness and a pointlight at the players position.
But it doesn't really matter which way you do it.