3. Mega Man Legends Series
Capcom hasn't done much with the old Blue Bomber at all as of late. Perhaps some of that can be attributed to the fact that Mega Man was a side-scrolling star who had a bumpy transition to the third dimension. While Mario survived and thrived, Capcom's attempt to reboot the series and gameplay with the "Megaman Legends" series went the way of the werehog. The storyline cast our hero as a tomb raider of sorts, seeking out ancient technology with his adoptive family and fending off the attacks of a trio of kooky pirates and other miscreants. The series had one sequel, which left Mega Man stranded on a planetoid with no means of escape while the people of his world still faced imminent destruction. Despite the adoration of the game's fans and a more positive response from critics for the sequel, the cancelation of the third title likely ends the story with Mega Man stranded and left to start a moon civilization with two immortal robot babes. I can think of worse fates.
This entry doesn't really count, because we all know that Half-Life 3 is going to come out any day now. Right? I mean, so what if it's been almost six years since the last one came out? It's going to happen, damn it! Valve's mega-hit starred voiceless scientist Gordon Freeman, whose background as a physicist prepared him for a life of heroically launching radiators into alien oppressors. While every entry in the series left off with a bit of a cliffhanger, the promise of episodic content every year for the sequel made the wait bearable. That is until Valve decided that no, actually they weren't interested in episodic updates after all, and went off to build other successful franchises and become a leading downloadable content provider through their Steam service. This leaves the fate of Gordon and his allies up in the air with the Earth still in peril, a major ally dead, and a planned expedition to an Aperture Science ship that could potentially bridge the Portal and Half-Life universes. We still don't know what's on the ship, much about the nature of the Combine's advisor masters, or if we'll ever see good ol' Doc Breen again (as was hinted at the end of Half-Life 2). Of all the titles listed here, Half-Life saga remains the strangest in that every entry in the series was a critical and commercial success. We can only hope we get a final chapter before the kids you don't even have yet are old enough to ask, "Dad, is Half-Life 3 ever going to come out?"
Among the most storied of the unfinished sagas in gaming history is Shenmue, which follows a young man's quest to seek out the Chinese crime lord who murdered his father. Meant as a trilogy, Shenmue did get one sequel, which is all the more impressive considering it was initially released for the ill-fated Dreamcast and was noted for having an extraordinarily high development budget. Along the way, Ryo beat his way through several street gangs, asked about sailors, drank some soda, and learned that his father's death was more than a blood feud between two fighting masters there was magic and shit. But before we had we a chance to unveil the power of the sacred mirrors and its connection to your character, the story was TKO'd. Ryo's desire for vengeance was just no match for poor sales, leaving the plot threads hanging just as Ryo was about to collect a magic sword. A magic freakin' sword and then, boom, nothing! Though it has been almost twelve winters since Ryo last martialed his art on some punk, diehard adherents continue to cling to an undying hope for a miracle, or a successful Kickstarter campaign. Probably have some pretty sweet rewards for donating $35 million.