There is a spawn limit at any given time, which equals 6 + (10 / difficulty). Maybe some enemies clipped out of bounds, didn't get deleted properly or maybe just hid in the level. I didn't really test the spawn limit all that much. I just adapted one of my public libraries during the last day (and was made on a plain text editor lol).
I completely forgot about the clipping issues, it is due to the hull being too far away from the rotation axis of the cabin
The UI MAY clip out of bounds at certain resolutions due to how the shaders work (they depend on the PoV from the camera). Just another thing i didn't get the time to make as stable as i wanted.