One thing that irks me in films and games is when people die instantly - you’re not going to instantly die from a bullet wound in the arm, nor are you going to instantly die from a stab wound to the stomach.
How realistic are deaths going to be? Large battle scenes are mentioned, meaning that there are going to be many fallen combatants. Are people going to be slowly bleeding out, screaming in agony until they reach the inevitable, or are they going to drop dead as soon as a weapon touches them?
A game called ‘War of the Roses’ has a ‘finishing’ system, where when you’ve been beat in combat, you can either yield or be killed - if the player chooses to kill you, they literally pull up your visor and stab you. Although this is somewhat graphic, it displays the realism.