Thank you so much for playing the game and for the very detailed feedback!
The hit registration bug is caused by the fact that you're hitting the enemy weapon instead of their body. This also applies when they shoot at you and will hit your weapon or the object you're carrying if you have telekinesis. Whenever a damageable part is hit you'll see red particles on impact. Otherwise the particles are white.
The enemies spawn and despawn based on the area. For example, when you enter the building with telekinesis upgrade, enemies on the top floor spawn. When you get close to the floor below, where the upgrade is, the enemies on the top floor despawn and the ones below spawn. Unfortunately it's not a great system. If you push forward doom-style, you won't notice it most of the time. But if you play more defensively and fall back it becomes visible.
I'm glad you liked the telekinesis ability, it is the core of the gameplay. I wish I had gotten to do more with it, but it is what it is.