Konami‘s “Akumajō Dracula” was first released in 1986 for the MSX2. It set the template for a series that is still going (relatively) strong to this day – the Castlevania series.
This MSX game was also the first game in the Castlevania series to be given an English language release, and it was released in 1987 in Europe under the title of “Vampire Killer“, which then changed to “Castlevania” when the North American NES version of this game was released on cartridge.
That said: Vampire Killer is meant to be a “parallel version” of Castlevania, running alongside the main series, but to be honest I don’t really know what that means other than this being some kind of “alternate universe” that it takes place in.
Playing Vampire Killer now is still fun and contains most of the elements that became popular as the Castlevania series developed: scrolling platform levels with doors, interconnecting passages, an army of horror-themed opponents and the occasional full-on boss fight.
While Vampire Killer does lack the depth and variety of later 2D Castlevania games it is still a game worth playing now.