Played through on both normal and hard. The sound design was nice, but neither mode offered much in the way of gameplay. I just walked around, picked up items, then walked back. There didn't seem to be much point in engaging with the enemies at all, and they didn't seem terribly interested in engaging with me either (I followed a few around, tried to get them to aggro with varying levels of success, then just walked away). For large stretches, there weren't any enemies around at all. I think it really would've helped to tighten up the map (less empty space) and increase the threat of the enemies (more of them, more aggressive, more dangerous when they do aggro) to keep pressure on the player (and maybe give them a reason to use those bullets).
The constantly depleting health also didn't add much pressure. I found you could just ignore it if you were walking around looting since you'd always get enough health to stay topped off.
The music was nice, and I enjoyed the somewhat spooky/mysterious atmosphere while exploring the map. The reticle narrowing when focusing on enemies was a nice touch.