Thank you for your feedback. Makes me very happy that you already enjoy the game in the current state!
You aren't the first to mention that the game is too dark. I guess I haven't found the right balance for it yet and it most likely could indeed use some more lights. I also like your idea of making dropped items glow. And more guns are a no-brainer and definitely happening ;)
I haven't decided about the health yet though. However I definitely also want to have some more game modes to use the guns and mechanics in different settings as well.
I will definitely consider all feedback. Keep it coming and thank you!