It works fine in “very dark” conditions, but if you move into an area of “shady” or “cloudy” lighting, your vision range is seriously reduced compared to very dark. The easiest example of this is moving next to the computer console in the starting evac shelter. if you’re standing two squares away from it, you can dimly see up to five squares out. If you’re one square away or adjacent, it’s pitch black beyond your adjacent squares. What’s up with that?