Since I have some knowledgeabout how long Japanese sentences work, I think I could shed some more light on one of the sentences ("As you can probably gather from the fact that Vampire Killer is set in a different era from the previous games, the scenario is unique to the Megadrive, and is my personal conception of the Dracula series.") As I don't have acces to the original text, this I just a feeling I have so I can't proof it (for now).
Basically, the sentence structure is like this: X, Y, Z. Each section of the sentence gives more background about the section that precedes it (Y gives more background about X, Z gives more background about Y). For example the sentence: "Mathias became a vampire because he was angry with God about the fact that he caused the death of his wife"). X= "Mathias became a vampire", Y= "because he was angry with God ", and Z= "about the fact that he caused the death of his wife". X is the main sentence and Y and Z add further details. In Japanese the order is reversed. In that case the order of information would be: Z, Y, X.
So what I think might have happend is that translator made a mistake and translated in the wrong order. Ignoring for now what "personal conception of the Dracula series" actually means, it's possible the sentence should be translated like this:
"This is my personal conception of the Dracula series, since it's a scenario that is unique to the Megadrive, because Vampire Killer is set in a different era from the previous games . "
(In a normal English translation this information would probably have been split up in two sentences).