I think I know what Gordon Freeman's emotions would be like:

Disgust: " 'Please proceed to the next area.' I bet you've never done a hurdle in your life, fatboy!"

Anger: "MY EAR! I GOT SHOT IN THE EAR! WHY IS THE BUILDING TRYING TO KILL ME?!?!"

Fear: "That sniper shot at me and practically herded me into this tripmine!"

Joy: "You hear that? I think that's silence! That's the sound people make when everybody trying to kill me is dead! AND I HAVE A ROCKET LAUNCHER!"

Sadness: "Oh, shit. THEY KNOW MY NAME! FUUUUCK....This changes everything!"