None of these shots are very good.
Yellow is a clear miss and you'll need to be quick to put in a second one while he is running away
Red, you are aiming above the eye and already shooting upwards. the brain will be in line between the bottom of the ear slit and the eye. So will be a miss, maybe a stun in this case.
Green, is probably the only surely deadly one, by at least getting one lung, but you better have some good solids, as you might need to punch through some bone there.
From this angle, to get to the brain, you would need to shoot just above and to the right of his eye.