I sort of agree with gogeta, goku fringe needs to be a little longer, possible bring it down over one of his eyes.
Also, the hair at the back needs be thick and longer, though just at the bottom ( personally i think it thins out a little so early )
also the neck looks a little on the thick side, but that might be the way u've angleed it ^_^
other then those miner points, the model is very very good, specially for half life
( dont take any of my idea's the wrong way, i mean them in the nicest way possible
)