The game mechanics where great aswell as the art and design, the music and SFX could have been better. It also should have been set in 1917.
Regarding your philisophical question at the end, I think it's fine to kill evil.
Regarding your response to the philisophical question at the end, doesn't it make you evil if you kill evil ? (or anyone really)
Well if you look at it like that then wouldn't the allieds in the second world war be considered evil?
Maybe we're all a little bit evil...
If you're interested, I made an alternative cover art design.