Worms (The original) WormsUnited? (The original plus Reinforcements expansion pack) WormsTheDirectorsCut? (An Amiga-only release, reckoned by some to be the best of the bunch. A surprising number of weapons debuted here) WormsTwo? (The first of the "second generation", made major graphical leaps and had more weaponary) WormsArmageddon? (Even more weapons, better online play and missions) WormsWorldParty? (A remake of WA in many ways, but added enough to make it interesting) WormsThreeD? (They pulled it off surprisingly well. Not as good as some of the older games, but better than, say, LemmingsThreeD?) WormsFortsUnderSiege? (New game in development)
Plus two spin-offs:
WormsPinball? (A... well, a pinball game :-p) WormsBlast? (Um... Puzzler meets shoot-em-up?)