really cool concept, great implementation of the theme, you got something here, few feedbacks to help:
1. some animations to the player would really brought this home, but I understand the time constraints
2. sometimes I can kill the mobs without any threat, they just don't detect me and I use the shadow to kill them
3. something feels a bit awkward with the key combination + the mouse, a lot of times the attack didn't work for me, also some indication for cooldown might be good like a disabled sfx
overall really cool concept and keep at it! well done <3