Although the various consoles by Nintendo (NES, SNES, and Game Boy) had all received various iterations of the Castlevania franchise, until 1994 Sega's consoles had not been equally blessed with the series. For many Castlevania was considered a Nintendo franchise, even though it was owned by Konami and had seen ports of the original games for various computers and console-hybrids. For whatever reason (maybe the limitations of the hardware, or the seeming dominance of the Nintendo franchise), it was ten years after the start of the Silver Age of Home Video Gaming (arguably in the Bronze Age) that a Sega console finally received a Castlevania game, the rather ambitious Castlevania Bloodlines (titled Banpaia Kira, "Vampire Killer", in Japan and Castlevania: The New Generation in Europe).
Reportedly the plan for the game was for it to be a port of the SNES title, Super Castlevania IV. Nintendo, however, had very detailed licensing contracts and one of their stipulations was that games released for their hardware first had to remain exclusive to Nintendo brands. Thus Super Castlevania IV couldn't be ported to Sega's hardware even though the team had (at least allegedly) already begun work rebuilding the game on the Genesis). Instead, Konami had the team take the ideas they had, along with their technical know-how, and build a new game in the series: Castlevania: Bloodlines.
This new title starred two heroes, John Morris and Eric Lecarde, each on a quest to destroy Dracula and Dracula's niece, the evil vampiress Elizabeth Bartley. John, armed with the Vampire Killer, was after Dracula to uphold the duty of the Belmont clan (to whom he was related) and to avenge his father, Quincey (killed by Dracula is Bram Stoker's novel). Eric, meanwhile, was after Elizabeth Bartley for her role in the death of his wife. Armed with the Alucard spear (originally called the Lecarde spear in the American version, although that was a mistranslation from the original, Japanese name), Eric joined with his friend on their quests for vengeance.
Along with two characters (each who play more or less similarly aside from their differing primary weapons) the game featured an interesting twist on the standard Castlevania formula: although the quest starts at Dracula's castle it then leaves the lands of Romania, going all over the war-torn lands of Europe. The levels were long, featuring nods to various previous stages in the game (such as the "Munitions Factory, Germany" bearing strong resemblances to Clock Tower and Machine Tower stages, or the "Palace of Versailles, France" containing elements that would later compare to the Gardens, Marble Gallery, and Villa sections of many games). Although the title only featured six stages, the variety of elements, and length of the stages, provided an expansive platforming quest for players.
But while the game was the best Castlevania ever released for a Sega system up to that point -- by sheer fact that it was the only one as well -- it did lack some innovations from previous games. Although there were two characters, you couldn't switch them out at will (unlike in Castlevania III). And while you have a Belmont-style character that can minimally swing from ceilings and platforms, John doesn't have the dynamic whip abilities that Simon Belmont exhibited in Super Castlevania IV. Both heroes could upgrade their weapons an additional level (over the standard three), though, at least until they take damage (which negates the collected fourth level).
Additionally, while the various sub-weapons are included, many function differently than normal. The standard cross is replaced by the boomerang, which travels at a c-shaped arc instead of the usual back and forth. Meanwhile the axe now functions more like the basic cross, traveling out and back instead of the expected upward arc. These are weird changes that take a little getting used to, and seem like strange modifications indeed to introduce to the venerable series (changes that were immediately reverted back in the next games in the series).
The game is a milestone entry, none the less. It was the first game for Sega-produced hardware (of only two, the other being a Saturn port of Symphony of the Night). And it did introduce the full Dracula mythos to the series (even if not much was done with it later). Whatever can be said about the game and how it plays, it's at last memorable for that. Sadly the game didn't do that well on Sega hardware, selling a reportedly dismal 40,000 units over its lifetime, which may go some way to explaining why we didn't see more games in the series on Sega hardware. That leaves the legacy of Bloodlines as that of an also ran, an ambitious (if strange) title that never found its footing with the audience it courted.