Battery-operated flashlights
#1One room I ran into was pretty dang dark, and it was IMPOSSIBLE to see anything. I could just hear 173 moving around in the room, and it was pretty creepy. He even made that horror noise eventually and I just ran for my life out of that dark room. I'm not sure if it was me or not, but that room was pretty scary! One tool that would be a nice addition to the game is the flashlight, or a spelunker's helmet or something. It would illuminate a certain radius, with the use of the batteries in-game. With the flashlight you could incorporate completely dark rooms specifically for flashlight use, so you can move around and find necessities in the darkness. Also imagine the horror of lighting up a room to find 173 staring at you!
Another mechanic that would go nicely with the flashlight and all battery-using electronics overall would be the concept of batteries actually running out, so you have to be careful and strategic with battery use. That is all 
"Yes, it's a goddamn nuke, but if 682 survives and adapts we'd be boned beyond belief."
