Not in, but I would say Worms 2.
The first generation Worms games (the pixelated ones) are imo quite outdated. The projectiles flight path seems somewhat weird, they fly very fast, and homing missiles can change direction too suddenly, with almost no curve. Damage gain also seems a little random, and some of the weapons are overpowered, like the Air Strike.
I also don't like the 3D worms, mainly because hitting enemies is much more difficult, as is moving about because obstacles tend to block the view sometimes (meaning, the camera is a little bit bad)
But with the cartoony style 2D Worms, everything is perfect. Everything looks nice. It's easy to move inland and whether or not projectiles hit enemies, is only up to you and not whether or not the camera is blocking your view, or you couldn't predict how certain projectiles would behave. Worms 2 also has the best customization options in the whole series - be it maps you want to customize or weapons. Bazookas doing too little damage and a hole not big enough? Boost that fucker to do 200 damage and a hole the size of a quarter of a map. Cluster bombs not dropping enough clusters upon explosions? Five's too little a number, let's make that 25.
I've played almost every Worms game ever, but I've spent by far the most time playing the cartoony 2D Worms games (for example Worms 2, Armageddon, Worms World Party and Worms Reloaded) because they're simply the most fun and everything's just perfect. And given the fact that I've put 666 hours in Worms Reloaded, speaks for itself.
tinyE: I just asked this in another thread but here goes, which Worms has the best SP? I was always under the impression that none of them had any SP beyond some luke warm skirmishes. Giving a pass on the Cultures games because of my investigations so it frees me up so more cash for these.
Again, I would say Worms 2. No Worms game has ever had a campaign that's actually great and long: it's always been mostly just a tutorial in disguise, so that you're better equipped when it's time to hit MP. But if you enjoy battling against bots, then Worms 2 is the best choice in this field too, again because of the customization options. Worms 2 lets you battle against more teams simultaneously than the other ones, plus I think Worms 2 was the first game in the series where you could decide the number of worms in any team (say, you wanna give yourself two worms and four worms for the other teams - that's totally doable). The AI difficulty is adjustable (just don't expect them to use Ninja Rope), so the challenge should always be on the same level as your current skills.