I can describe it quite well, but what I try to create on the art side of things just doesn't look the way I want it.
Basically, I see the Doom guy, helmet off and completely beat up. You can tell he's fought his way through the hordes of demons with how bruised and cut up he is, certain parts of his armor has been torn open along with scratches on his arms. He's holding a shotgun in one hand and his other hand has nothing. He's exhausted, but knows he must soldier on, thus is his task. He may win, he may not, but one thing is for sure; he won't stop fighting.