Well I mean, I would have thought a not gate would check which wire and output to that same wire. I thought an AND gate and those types would require two inputs before they could do anything though.

The NOR and NAND gates fill that role pretty much. The annoying bit with trying to make a NOT gate is that with 4 inputs and outputs, things get a bit screwy if you try running multiple inputs through a NOT (if 1 input is on and another input is off, what would it output?). The NOR and NAND circumvent that by checking all inputs for the same behavior.

I added the output inversions to the new sensors just to simplify that part.

Why isn't there a not gate in this game? :| A signal inverter that is.

I had not considered it, but I'll think about it.

Any plans for 360 turrets?

Nice mod