(I should reaaly be studying for exams now but whatever)
A classic I probably sank hundreds of hours in on my old 360.

Campaign is good. Not quite as good as the original. Imo, if you've played it once, there's really no need to play it again.

Multiplayer is fundamentally good, but in the present day, I'd avoid public games to to hackers. Not super fun getting killed by a hacker. For playing private games with your freinds, however, it's great, with a wide variety of cool gamemodes to pick from.

Zombies has the best maps and the worst maps in the series.
Tranzit and it's ilk are awful. Defenitley playable but very weak and annoying, espescially solo. (town can be a bit of good clean fun, tho)
Nuketown is a difficult, simple map. Kinda reminds me of Shi No Numa just in it's simplicity level.
Die Rise is mediocre. Cool setting but poor execution results in a boring map with some frustrating aspects.
Buried is pretty alright, easy but has quite a bit of innovation. Another cool setting, this time done well. Good for bad and good players alike.
Mob of the Dead is reaaaaly good. Very well rounded in every way possible. Great innovation, tons of stuff to do without in feeling like a to do list, fun solo and with others, just great.
Origins is also very good, but not quite as good as Mob. While the setting is better (I feel, at least) and the map is very replayable, it's just a tad less amazing than mob. I feel like I'm underselling it; it's still tiead for my second favorite map alongside Der Eisendrache. It also got remastered in BO3 but it's kind of a cakewalk there.

(I should reaaly be studying for exams now but whatever) A classic I probably sank hundreds of hours in on my old 360. Campaign is good. Not quite as good as the original. Imo, if you've played it once, there's really no need to play it again. Multiplayer is fundamentally good, but in the present day, I'd avoid public games to to hackers. Not super fun getting killed by a hacker. For playing private games with your freinds, however, it's great, with a wide variety of cool gamemodes to pick from. Zombies has the best maps and the worst maps in the series. Tranzit and it's ilk are awful. Defenitley playable but very weak and annoying, espescially solo. (town can be a bit of good clean fun, tho) Nuketown is a difficult, simple map. Kinda reminds me of Shi No Numa just in it's simplicity level. Die Rise is mediocre. Cool setting but poor execution results in a boring map with some frustrating aspects. Buried is pretty alright, easy but has quite a bit of innovation. Another cool setting, this time done well. Good for bad and good players alike. Mob of the Dead is reaaaaly good. Very well rounded in every way possible. Great innovation, tons of stuff to do without in feeling like a to do list, fun solo and with others, just great. Origins is also very good, but not quite as good as Mob. While the setting is better (I feel, at least) and the map is very replayable, it's just a tad less amazing than mob. I feel like I'm underselling it; it's still tiead for my second favorite map alongside Der Eisendrache. It also got remastered in BO3 but it's kind of a cakewalk there.