The full version of the game had all of it's lighting updated including skylights, lightmass volumes, post processing, atmospheric fog, and more. I have a sample video on my YouTube channel.
Unfortunately, the demo has a small glitch where the flashlight gets really dim due to a battery life mechanic I had in the game but partially removed. The mechanic would cause your flashlight to start dimming when the battery got low. After I removed the mechanic, or at least I thought I fully removed it, the demo would automatically set the flashlight to it's lowest possible brightness setting.
Issues are resolved in the full version. Thanks for trying out the demo!