YMMV / Call of Duty

• Even Better Sequel: United Offensive is seen as a massive improvement over the already impressive original game, thanks to the addition of new weapons, vehicles, and multiplayer maps. It's telling that World at War five years later tried to innovate on the CoD4 multiplayer by bringing back mechanics from UO.
• Fan Nickname: Quite a few people who discovered the original, United Offensive and Call of Duty 2 after playing the next-gen games are now calling them "Call of Duty Classic". The first game was released with this title as a downloadable game after Modern Warfare 2's release.
• Franchise Original Sin: Call of Duty: Vanguard caught flak for its highly anachronistic take on the war, but Call of Duty fudging historical accuracy for gameplay or story purposes dates all the way back to the first game of the series: perhaps most notably are the endings to the American and British campaigns depicting, respectively, a wholly-fictional mission to rescue prisoners from a Dulag Luft camp and a two-man infiltration of the battleship Tirpitz that never happened. The difference with the earlier games is that they at least had a dedication to historical authenticity - for instance, given the insane amount of time and resources the British put into trying to sink the Tirpitz, it's easily believable that they would have sent a pair of SAS commandos to plant bombs ahead of one of their many air raids - and the errors they made tended to be extremely minor, e.g. the StG 44 showing up in its production form in 1942, instead of modeling a slightly different prototype variation that existed at the time and was superficially near-identical. Even Call of Duty: WWII, which could be considered the start of the real problem (made by the same dev team as Vanguard), was half-and-half with this: the dev team admitted that player choice took precedence over historical accuracy for multiplayer, but that the campaign would be as authentic as possible, with its most notable errors only being on par with those made in other games e.g. several Russian guns showing up in German hands (an extremely common occurrence in reality, "wrong" only because the game doesn't include the theater where they had common access to Russian guns). Vanguard's problem was simply taking a step beyond that by choosing to focus its singleplayer around a special forces group with far more women, people of color and Axis defectors in it than would realistically be allowed in the 1940s to handle the kinds of operations CoD usually depicts special forces undertaking, to say nothing of how much wackier the multiplayer got - to give a good idea, despite the multiplayer ostensibly also being set during the war, it includes a map taking place on the set of the first Godzilla (released 1954), allows you to play as Snoop Dogg (born 1971), and as of its final seasonal update includes the F2000 assault rifle (entered production 2001).
• Hilarious in Hindsight: The protagonist of the Russian campaign in United Offensive is Yuri Petrenko.
• Nintendo Hard: United Offensive's campaign was considered to be very difficult during its release. The actual gameplay was identical to the first game, as expected from an expansion pack, but the new weapons gave the Germans an edge they didn't have - the Germans (and the Russians) got a semi-auto rifle to match the Americans having two in the first game, and suffice it to say, it wasn't tested quite well enough in the hands of enemies. Fights that wouldn't cause one to break much of a sweat with the original game only giving them MP 40s and Kar98s become nail-biting tests of endurance (and patience, and hammering the quicksave key) as enemies that were only a problem in extreme close range suddenly paste you in two shots from a hundred yards.
• Older Than They Think: United Offensive was the first game in the series with a Sprint Meter, though it was bound to a different key (Alt by default) and covered a much shorter distance before running out; it was not until Call of Duty 4 that it became ubiquitous in the series.
• Sequel Displacement: A vast majority of the fanbase have never played the original game, United Offensive or even Call of Duty 2 - the current CoD fanbase largely consists of console gamers while the first game was (and United Offensive still is) exclusive to PC, and the series didn't become the household name it is now until Call of Duty 4.
• That One Level:
  • Pavlov's House is a nightmare even on Normal difficulty, specially during the last segment of the mission where you have to defend the house from a German counterattack with respawning German soldiers trying to Zerg Rush you constantly while having to destroy tanks with stationary anti-tank weaponry.
  • The second half of the Foy mission in United Offensive comes to mind. As if sniping tankbusters while EVERYONE IS SHOOTING AT YOU isn't enough, the final part of the mission is just as brutal.
  • The very last sections of both the American and Russian campaigns of United Offensive force you to wait for German tanks to show up and be destroyed, while soldiers respawn infinitely. In the American mission, they are so frequent you may not even get enough time to reload your Panzerschreck; in the Russian one there are also soldiers firing at you from afar, and a Stuka doing frequent bomb runs - it may even destroy the artillery piece you can use and force further exposition to scrounge for Panzerfausts around.