Jeez guys stop bitchin, look at this work, you can tell he worked hard, to create something totally custom and super sexy, in his own time, even though he didn't have to.
So what if some content is from valve, he's not selling anything, I used sounds from F.E.A.R and Doom 3 in my game, but so what, and like he said its being protected with FPSPack, so what the hell have valve got to lose, they're a Multi-Billion Doller busness why the f*ck are they going to get p!ssed off over one measly non profit game.
I think you're all jealous because he's better than you so you think "oooohh If I cant do that im not letting him" and like he also said, the HL2 zombie is used a lot, and i've never heard complaints about that.
So shut the hell up and let him get on with it!