Call of Duty: Modern Warfare introduces certain new gameplay mechanics to match the level of realism the studio is aiming for with the game in Multiplayer.
One of the new things is interactions with doors in Call of Duty: Modern Warfare MP. Players are able to open and close many of the doors located around the maps, and can also brute force charge into doors for those who want to sprint into places.
Brute forcing into the door actually can kill an enemy if they are standing next to the door on the other side.
Another new mechanic is the mounting. Players are able to mount onto surfaces to watch over ledges across the maps in Call of Duty: Modern Warfare. Alongside this, players can mount to lean over certain areas. The leaning is much more intuative than it was in Call of Duty: Ghosts, and could be more useful in this game than in the previous one.
With this game, both mounting and leaning are not automatic. Players have to press R3 (on PS4) to mount when it’s available.
Another new mechanic is also the Tactical Sprint feature that the studio has added. Standard sprint is available by pressing down the left analog stick, but if you press down twice, you enter a new tactical sprint where you hold your weapon up and get a burst sprint to get around a little faster.