Design-Wise:
I think you (do we address lord yahtzee directly in these parts?) are overlooking the genius of evolution. Legend tells that mario has a moustache because changing a couple pixels made his 8bit face clearer. So it was GENIUS design back when it first arrived. yeah?
The way they've chosed to evolve the character since then is the thing to argue. Somehow he's become this bouncy perfectly rounded mickey mouse. I doubt it's an accident. He has gotten so far from "italian plumber" that it's kind of crazy. but maybe that's also a good movie.
I wonder if the agent 47 barcode is a similar example. a detail that's there for the closeups, but not really core to the design. Which to me is just well dressed baldy, with gloves. I hadn't played those games enough to know he always had a red tie. I'd guess this is meant to evoke just a splash of blood in the player's mind. (or is it explained in story? does it ALWAYS have to be red? could they one day do a multiplayer mode where different agents were only really discernable by goofy lifesaver tie colors). hmm.
Gordon freeman seems like a non character. in that you never speak, and your focus is on the hands. I think he must look freakish in his special coppery suit, when hiding out with rebels in rags. It works well in making you feel like you stand out. but. seems like it's worthless to discuss? since you just don't look at his character, and it's totally incongruous with the worlds he passes through, its design has no real relevance to gameplay? (maybe i'm missing something). Maybe it works on a subtle level, making you feel separate from whatever story you're in (which does seem to be part of the story's point), with just a dash of feeling like a spaceman.
I think it's more interesting to focus on the recognizable shapes of alyx and the combine bastards, and anything you look at and have to differentiate. (these designs are huge winners, yeah?).
...Gah. I still can't stand seeing Gordon's silly face (posters, book covers, box art). feels like the developers were just having a laugh. And now they're trying to make him sexy and sleek. but still horribly nerdy. so strange. i think that sbecause ... it's actually aweful. and nobody wants to admit it. because the games are so good.