Any game that takes enemies AND stages from the ghoul n' ghosts, demon's crest, and gods knows what other non-castlevania series, and tries to pass them off like they instantly fit in automatically fails in my book. Sorry but I see people doing it too much, and it just looks god awful. They really need to instead focus on the several THOUSAND enemies we already have for the Castlevania series and use them instead. It's one things to use effects, or even projectile edits that are not obviously noticeable, but whole enemies and stages from other games is just lousy.
On that note,2 stages are direct rip offs from the 2 series I just mentioned. And they are missing almost ALL of the things that made those stages originally at least half interesting. This guy obviously did a quick lazy job, and put in minimal effort into his own creation. Sadly I see this a lot, and it's truly a shame.

As for two player; it's not that hard to do honestly in a basic game like this.
Also complete fail on using darkstalkers intro directly ripped off too.
Here are a few examples of fan-games that are descent and have new ideas; sure there is room for improvement with most of them, but they are better than vampire hunters that's for sure:
Castlevania: Ballad of Autumn (Demo)Castlevania - Fangame Engine Test 2Castlevania 2: Simon's Quest - RevampedCV Lost Tales Test Video 4