Lt.Speirs has outdone himself yet again with this incredibly intense update to his CoD2 single-player realism mod. It focuses on parts of the gameplay with which no other mod has ever dabbled, so you're sure to get something new here! All I can say is that you just have to read the list of new things below; you might even consider checking out the full ReadMe for extended details. Once you do, trust me, you'll want to take the time and play this mod ASAP! ;)

Battle Chatter system fixed and updated (no continuously repeated death messages and AI tactics)
Most levels have more characters on screen (you can have anywhere between 10 and 35 guys with you)
The Du Hoc defense level has the tempo of the last battle of Saving Private Ryan (many lost men and ground)
Realistic allocation of NCOs (1 Sergeant and 1 Corporal per 10 Privates)
Various map-based changes
NCOs for the Americans (unlocked Lieutenant, Sergeant, and Corporal uniforms for the Americans -- the AI will even call out ranks from time to time)
WCP's Allied Pain mod -- where would realism be without WCP?
69 new death and pain sounds for AI
WCP's Tracer mod
Realistic grenade blast radii
Realistic suppression system
Realistic AI aiming -- NPCs no longer take ineffective 'pot shots' -- cover is your saving grace -- you can't lone wolf it most of the time; you must rely on your comrades for fire direction, covering fire, ammo, or at the worst moments... bait
Updated faces for all countries
The game is now up to 10 times louder in some areas for realistic war sounds
Realistic weapon characteristics
Frame rate booster
New weapons sounds from WCP's sound mod and various other games
Realistic skins from various developers like DeltaForceOperator, Rusty, etc. -- all credit goes to them

Lt.Speirs' Realism Mod