First of all, thank you for that comprehensive comment, I really appreciate it.
I've seen some conceptual arts of Daniel, however I don't know if they're really official. For example the game-cover, there was a Daniel made by the distributors, not by Frictional Games. Anyways, from what I've seen, I like all the Daniels people made.
I'm glad you like the drawing and crosshatching (this is actually the only way of shaing I know XD).
As for his expression- I decided to set him free from all the fear, since he's just realized what he'd done and what he must do in order to redeem himself. So there he is- ready to kick ass. (=
Thanks again. :3