texture for hl2 free ( spec + normal map )

Nice one. I have some comments on the normal and spec tho.

I guess what you would want for such a corrugated wall is some more depth.

This one may be a bit overexaggerated and too smooth. That really depends on the type of metal. Adding some bumps and dents into it will also make it a bit more interesting when the lighting hits it as it is now it only has information pretty much in the x-axis for that metal. Just very slightly tho since these things should be subtle ingame mostly. Judging from the diffuse it seems to be built with many plates bolted onto each other. Could be nice to add some of those plate seams in the normal too as well as the bolts, I didn't do that on this one tho...

[Blocked Image: http://philipk.net/other/normalxh6.jpg]

It's nice to see you have a lot of contrast in the specular but I think it would be way too shiny for such a material ingame, especially in HL2 as it's cubemapped (I know you canlower the tint tho in the vmt). But What I did was to lower the overall brightness on the metal part and trying to keep some highlights, plus adding some bottom/top darkness for dirt as well as some subtle outlines for the corrugated details just to help the normal out a bit to show more on the edges.

[Blocked Image: http://philipk.net/other/specdh8.jpg]

The diffuse looks very nice and the render is cool.

I hope I wasn't too picky, and this is just how I would have done it. There's no right or wrong