-More or different effects(More variety in the explosions and bullet impacts) The explosions are bigger and the battlefield looks and feels more chaotic.
-Realistic aiming(Rendroc's warzone for Brothers in Arms inspired me to do this for Call of Duty 2) remember when you aim, the weapon stays still? I have changed that, now it moves and feels like you are holding it in real life, I uploaded a video so you can see what it is like Moddb.com , the movements of the weapon simulate unwanted body movements made by heartbeat and all that.
-Stance movers(When you move, the weapon doesn't stay still, it goes down) The weapon goes in the sprinting position, but since I don't know how to add sprinting, you just move normally, the weapon position and spread changes.
-Sounds, these sounds are amazing in my opinion, they sound very vivid, I have also tweaked a LOT the soundaliases, now the battlechatter does not feel like someone is shouting right next to your ear, now the battlechatter is not louder than the explosion sounds or bullets being fired, when someone shouts, you will know where that sound came from, and you can only hear the person from a certain distance the weapons and explosions sounds feel very realistic, like you're actually in the middle of a battlefield, mortar sounds and artillery sounds are different, a mortar sound feels aggressive, and an artillery sound is extremely scary, most bullet impact sounds are taken from Band of Brothers, and Panzerschrek impact sounds are also from Band of Brothers, the bullet impact sounds are very aggressive. Also, the grenade sound depends on where the grenade explodes. The mortar incoming sounds are extremely scary, also, when a mortar team fires a mortar, a soldier there will scream "feuer" which means fire, I took that sound from band of brothers, you will hear a mortar being fired plus the feuer sound, but you can only hear the feuer sound from a limited distance, the mortar being fired can be heard from a long distance.
-Tactical gameplay, I have decreased the player moving speed, it is very unrealistic, it is too fast, and you can run n' gun easily like that, I tried a speed like in brothers in arms, but instead, it is too slow, call of duty is very intense and with that speed you will never survive, so I mixed them both and tried a speed that's in between, and it is perfect, it is not too slow nor too fast, and it gives you a lot of tactical gameplay.
-Player battlechatter, I am very proud of this one, I have added player battlechatter, in the old call of duty only your team mates and the enemy shout, but now it is your turn to be annoying! When you reload, there is a 9/10 chance that you will scream "reloading" or another random thing, when you throw a grenade, you will scream "throwing grenade!", but it is not the exact same sound all the time, to add variety, there is a random chatter sound for most things. I am still trying to figure out how to make it so that when you kill an enemy, you shout "enemy down" or when a team mate is down you yell "man down", and I wanted to say that in the american campaign, you scream with a young american's voice, like 24 years old, in the british campaign, you shout with a 30 year old's voice, and in the russian campaign, you do shout in russian, and i think you're around 35.
There is much more that I haven't mentioned but I think these are some of the main things.