Magnetization thing: I think it's something in the code relative to collision detection. Notice how the grunts move in clips? I think it's similar to player movement: if you don't reverse before the next clip - which may be related to how the game refreshes or something - then it's too late, even though you know you hadn't touched it yet, and the frame closes.
9 wave special: recently, I have sometimes taken diagonal directions, especially when charging groups of enforcers, and it has worked to my advantage. Yes, their shots are seekers. The best defence I've found is moving in a very tight quick circle and moving on in another direction from previous. Move in a line and it'll almost always get you.
overlayed objects: this is just how the game is. They're like non-interactive particles that can pass through each other, and you're anti-matter.
pausing the game: sometimes I don't do as well when I come back. Sometimes I do as well or better. If I'm totally relaxed AND up to speed with the rate of the game, I'm golden.