http://en.wikipedia.org/wiki/The_Last_Express - http://en.wikipedia.org/wiki/The_Last_Express

It's set in the last Orient Express that travelled to Constantinople (it's not called Istanbul in the game - sorry) and I found it amazingly well put in place in time. It shows the rising tensions between the nations, the characters are incredibly well developped, it's absolutely not linear and the whole representation is 100% realistic.

Artistically it offers a very rich soundtrach and a combination of 2D-rendered graphics that I think hasn't appeared in any other game.

You can see some of its cutscenes here:  http://www.youtube.com/watch?v=f8vfrwm_AzQ - http://www.youtube.com/watch?v=f8vfrwm_AzQ . Notice that you only get subtitles for some languages (e.g. for French and Russian but not for Serbian) but not for all of them. In fact only the languages the main hero is supposed to speak get subtitled, in order to give an as realistic experience as possible! This is just one of the many details that make it so good.

In general it's an excellent piece of software that of course did not sell well, and it's probably my second favorite video game.