the game needs not just a little bit more lighting:
it needs to be a lot brighter to see anything.
no, the game would gain atmosphere because it would be possible to see the game and play it. the important thing for a dark atmosphere is not so much physical darkness, but limited visibility from most of the screen being black.
making a scene almost completely black to create a very dark atmosphere works for movies because the movie continues even when you don’t understand anything. this doesn’t work for games because games can only continue when you can understand them.