OK this is pretty awesome! I think there needs to be an indicator for what you've swapped so far. I couldn't work out if it was like portal and you shot one then the other, or your current speed got swapped with whatever you shot. If you had an icon in the bottom for what you'd be swapping with the next thing you shot, that might help make things more obvious.
Also HUGE improvement in presentation from the last one! Keep it up!