I can't find it now, but someone made an ultra-realistic D-Day simulator where you basically portray one of the guys who never made it to the beach in Saving Private Ryan.

Battlefield 1 opens with a series of short battles that you can't win. Every time you die the camera moves to another nearby soldier who is also being overrun, and you fight for a while then die again. You see the graves of each person you played who died. It's one of the most powerful openings of a war game I ever played and really drives home the reality that whilst what follows is fun, the real WW1 is one you probably would not have survived.