Vampire Killer is more notable as a historical document than as a game. Simon's Quest and Symphony of the Night did not come out of nowhere; design concepts for later explorative Castlevania titles originate here. Its proximity to the original Castlevania and concurrent development indicate that explorative gameplay was being considered as a primary gameplay style from the series' inception. This revelation is fun to think about, but the game itself is awful. Game feel, design, mechanics, all are unacceptably poor. Watch a gameplay video, stroke your chin and think "huh, pretty cool how far back some of these ideas go", then move on. I managed to finish it with save states, and would not consider doing it any other way.

As a side note, Backloggd's description of this game is hilarious. I have no clue where it's sourced from, but it's so funny and SO inaccurate. I love it, and I hope it never changes.