I think this game is an excellent concept and, in terms of atmosphere, is perfect in my eyes, the graphics and audio are brilliant. The shooting also feels really nice and I like the idea that you have to use the light from the enemies to survive the darkness.
As others have noted, moving seems to be quite difficult and I found my clicks were ignored very often. I'm not sure if this is related, but this error appears in the console constantly from game load, even if I'm not doing anything.
`SCRIPT ERROR: attempt_to_move: Invalid get index '0' (on base: 'PoolVector3Array'). At: res://character.gde:1178`
I'm not sure what RPG in a Box will allow, and it's not a massive deal, but it would be good if you can hide the console from the player for a potential final release.
All that being said, I really like what you've done here and hope you continue to build on it in the future!