You know what else it might be?
Your brightness and gamma settings in Half-Life's video options.
If that isn't it:
Lastly, try to play around with some RAD parameters.
-texreflectscale
A smaller -bounce value like 4 (default is 8, and 9 on -extra).
-gamma
-texreflectgamma
Or, you can use -notextures and see what happens (though, I advise against that :P).