The art (yes ART!) of translation is all about translating what's being said, not what's being said. In other words, if you look at a string of words and grammar and translate each individual thing, you will fail. Miserably. When translating, there are two things that NEED to be kept in mind: the translation needs to convey all the information the original does, and the translation needs to speak with the same characterization as the original.
As an example, when translating dialogue you look at what the sentence is saying, not just at what the words are saying. Once you know what the point of that line of dialogue is--what information is being literally conveyed, you then need to look at how it's being said. This is especially important in games without spoken dialogue, as the player can't try to get emotion or characterization from the vocals (as there aren't any).
How does all this apply to Policenauts? Take the snipped DS posted. I would likely have erred on the side of including some of the stuff that was snipped. It's a personal preference, and one that every translator must figure out for themselves. Some prefer the more heavily localized route, others do not. That said, however, Marc absolutely NAILED the tone of the dialogue. Reading the text gives a ton of insight into the character just by speech pattern and word choice. I do not think it could have been done better in that regard. Seriously. Well done!
Something else to keep in mind is that one cannot judge a game translation solely on the video subtitles. I believe it was mentioned before, but there are certain constraints one is under when subtitling that don't really exist when all one has to worry about are boxes of text.
Anyway, rant over, etc. Suffice it to say that this translation is a brilliant job. Yes, there are some things I likely would have done differently, and other things that DS would have done differently, but show me two translators who would do a game exactly the same way and I'll see about getting you some tickets for a ski vacation in Ye Olde Subterranean Land of Fire and Brimstone. Marc clearly understands the essence of translation (and with him being a professional tranlator, I'd sure hope so), and I don't think anyone playing the game is going to have to worry about lost in translation type stuff.
Good on ya, Policenauts team!