I like the art. Camera angle is nice although clipping could use work, and might benefit from being more zoomed out. Shooting controls are interesting. Consider grid style movement, it would make lining up shots easier.
This first level was wayyyy too easy, maybe think about upping the difficulty so that the player feels under more pressure, I think this would lean into the theme nicely.
Extra points for using UE4.

Visually really good.  Loved the music.  Movement controls were good, but the aiming was a bit awkward.  The camera occasionally got stuck on the landscape.