The last mission, The Last Stand, from Advanced Warfighter 2 might be the single worst level I have ever played in any tactical shooter.
To be honest, difficulties do not change the game all that much. Compounded with two or three checkpoints throughout an hour-long level, the game at times gets outright unfair even on the easy difficulty. The large maps make you think that this game is a sandbox and open, but the level designers enclosed the levels with machine-gun nests, walls, and "YOU ARE LEAVING THE MISSION AREA!" warnings, leaving only one possible way and route to beat the level. However, this only makes the levels rigidly linear. The reason why they are so ridiculously powerful is that the developers use machine gun nests in a way to encourage the player to take alternative routes to flank the enemies. I am not joking when I say they are pixel accurate. So, the most accurate and deadly weapon in these both games is not the sniper, but the machine gun nests. The worst thing about the game is the machine gun nests. The game encourages the player to climb the mountain and snipe the enemies, but apparently, guards just can see and counter-snipe the player with semi-automatic rifles in 80% accuracy? What? There is a night mission where the player has difficulty to see environments even with night vision, yet guards, who have no night vision, can see the player miles fucking away. Also, enemies seem to spawn out of nowhere when you reach certain event points and immediately fire upon you when you are on an unfortunate spot. It does not help your tactical map is so small, far smaller than both your and enemy's lines of sight.
So what happens is as soon as enemies literally materialize from distance, they immediately detect and kill you before the player can reasonably respond. Their visibility is the same as your max draw distance, which is incredibly limited and short. However, the bullshit part lies in how enemies have laser fucking sharp accuracy and sight. They have problems with close-quarter combat, coming out of covers for no reason, only to get shot and killed. This AI problem extends to your teammates. Whenever they act smart, it is often due to the arbitrary scripted events during set-pieces. They also just charge at the player without any plan. Enemies rarely hide behind cover, mostly stand in one position even when they get fired upon. Enemy NPCs are both smart and dumb in the worst possible ways. But the problems I will talk about are true to both games. While both 1 and 2 suffer from the same problems, Advanced Warfighter 2 is a marginally better and polished game.
And I genuinely think Advanced Warfighter series on PC might be the most bullshit difficult tactical games I have ever played.
I finished all classic Ghost Recon games, all OFP games, ARMA 1, SWAT 4, Rainbow Six Vegas 1, 2, Sniper Elite trilogy, the entirety of Delta Force games, Brothers in Arms, often on the hardest difficulty. I also have the XBOX360 version of the first Advanced Warfighter, which I might play later. I bought Advanced Warfighter 1 and 2 on Steam a long time ago, now delisted. If the main games are basically a reboot on the series like Rainbow Six: Vegas, the PC versions are spiritual successors to the original Ghost Recon: first-person military sims with far slower and deliberate combat.
PC versions are entirely different games developed by Grin. Apparently, the main games are drastically different games with a more casualized approach to the genre and a focus on shooting. I have not played the main versions (XBOX360 and PS3) of Advanced Warfighter series.