Of course realistic, however there are lot of limits, what makes it very difficult to create a really realistic game.
For example, realistic game needs very accurate physics - that means different trajectories and penetration capabilities for different weapons/ammo. Highly specific `damage` to objects and soldiers - there again are needed very accurate mathematic models of projectiles and objects, i.e. how objects `react` when they are hit by projectiles. For example again - consequences of HE round, fired in building, will depend from building structure and place where it was hit. So, to calculate all these physics `realistically`, very powerful hardware will be needed.
Other thing is, that realistic game request some other things:
- an accurate subordination of players;
- Logical scenario with some sense (ideal also would be development of scenario - i.e., most of next missions must be depending on results of previous missions).
- System of `injury` must be something like:
a) minor injury: bleeding (can be stopped with assistance of any soldier with use `small medikit` each soldier carries with him), an effect of `shaking hands` and lost ability to run, while still able to shoot. Stopping of the bleeding removes effects of `shaking hands` and `slowness`.
b) major injury: bleeding (can be stopped with assistance of any soldier with use of `small medikit`), lost ability to shoot and stand/walk/run (only crawling is possible). If bleeding is not stopped in X seconds/minutes, character dies. Ability to shoot, walk and run can be regained with `large medikits` (only `medics` have such kits with them and only limited amount. Additional amounts of `medikits` can be stored in bases, vehicles, ammo crates).
c) concussion: a near explosion or major injury can call concussion, a temporal unconsciousness. Only time (X seconds) is needed to get the consciousness back.
- Every soldier can carry only limited weight with him. One sidearm (handgun) and two small firearms are allowed: assault rifle/sniper rifle/SMG and LAW/secondary assault rifle/SMG. In case of MG/SAW, no secondary firearm is allowed. Underbarrel GL's like M-203 goes within the assault rifle it is attached.
- Equipment from dead soldiers can be picked up and used.
Imho the game with most of these things implemented is `Operation Flashpoint`.