The best Worms title to use a 3D engine.
Trying to fix things up, Team 17 developed Worms 4: Mayhem (2005). This one brought almost everything that was hanging in all the previews versions. The gameplay mechanics were improved and graphics are much more detailed in this updated version, particularly the smokes and explosions effects, which are now very similar as the ones in Worms Armageddon.
The weapons are cool, and the game has a lot of different game styles and a very good single player campaign, featuring 25 missions with some cutscenes in-between. Like in nearly all games in worms, there are locked features that you can only have access if you play the different game styles.
However, the best thing in this game is the custom maps. Unlike in the previews Worms 3D, the generated scenarios in Worms 4: Mayhem are simply perfect. In the configuration screen, you just choose a number, and the game will create a map with the setting of your choice. The map comes with a lot of objects, like bridges, mountains, houses (which you can occupy them), little rivers, caverns and much more. And, mainly, it's not that "island-like" maps as the ones in Worms 3D, that are easy to launch any of the opponents worms in the water. It's amazingly detailed map that you'll find in Worms 4, with walls and a lot of terrain that prevents this issue.
So far there aren't any patches for this game, but I really didn't notice a bug yet, except to a rare glitch that sometimes blocks your worm while walking, especially in areas that have several obstacles around.
I recommend to you to buy this game if you're a Worms fan, especially because you'll now experience everything with a proper 3D engine.