A *realistic* WW2 FPS

You'd start with a randomly generated name and a random intro cutscene, which gives your character a unique backstory.  Maybe you were drafted, maybe you volunteered, or maybe you're running from something darker from your past.  Maybe you'll fight for the Allies, or you could just as easily side with the Axis.  It won't really matter once you're in the trenches.  What will matter is everything you do once your feet hit the soil. 
You don't upkeep your rifle?  It might start to misfire, and eventually break down. 
You get grazed in the shoulder?  Your aim gets thrown off. 
Shot in the leg?  Better get that treated, you don't want to limp around everywhere. 
You can save as often as you like, but if you die, so does your character.  Forever.  The save file will turn into a tombstone on your save/load menu. 

What's your objective?  To win the War, or so they say.  All you really want is to live long enough to see the end of it.  War is hell, and should be treated as such.