COD4-Black Ops 1 was a solid run

1 and 2 were pretty good. A few cutscenes here and there and the rest is just good map design with a few scripted actions. 4 is still my most favourite Call of Duty multiplayer experience to day, but the single player campaign is so rushable even on the highest difficulty. It still has enjoyable bot butchering and cool Ac-130 and Capt. McMillian sniper missions. Gaz is still my most favourite Call of Duty character, alas deader than dead. 5 and 7 has some good cinematic experiences, like the WWII Pacific landings, jungle combat, bomber/fighter combat, CIA Vietnam memories, Russian Gulag rebellion. Plus 4 MP zombie scenarios can be pretty enjoyable. 6 has a few missions that are pretty cool, like the blackout night combats in the US cities.

Although I played up to 10, which is iirc Call of Duty Ghosts, they were mostly shit. I think back in 2018, I had learned the existence of a Call of Duty 1 expansion called United Offensive, which even at that date, after experiencing whole lotta shooters to that day like Arma 3, CSs, Battlefields, Doom, Quake, Halflife, Red Orchestra, Medal of Honor,.etc., still held up to a new fun mixed with nostalgia and fun on a game I hadn't played before.

COD didn't start until 4