I think you described the setting very well and your writing is excellent. I read some of the other reviewers' comments and I didn't notice any flagrant errors in grammar, etc, but I like to concentrate mostly on the story and forgive just about everything except blatantly misspelled words :).

I thought your story was very gritty and I liked it.

1.) “It’s play time.”
“Play time” should be one word.

2.) “...and the new moon calls to me in her (dark) glory.”

Wouldn’t it be ‘bright glory’, since the moon is luminescent? I personally think it would sound better that way, but it’s your story.

3.) “(But) still, the night is yet young, and my mistress() the moon() still sings her song.”
You never start a sentence with the word “but”, and you need commas before and after “the moon.”

4.) “It leads out of the alleys and up to a butcher’s shop(:) how fitting.”

That should actually be a semicolon.

5.) “It would not do for the gleam to give me away to a silent watcher I may have missed(,) not when I am so close.”

That also needs to be a semicolon.

6.) “The invitation is silent(,) most likely he does not even realize he has issued it.”

You need another semicolon there.

7.) “Upstairs, I spot light leaking out of a half open door.”

“Half open” should be ‘half-open.’

8.) “…innocent words carrying the sweet and blissful smell that nearly tears away my (self control) entirely.”

“Self control” should be ‘self-control.”

“The baby at first made a great deal of noise, but now lies happily silent in his cradle, little red polka dots newly decorating his blanket and keeping him in slumber.” I loved that line; the imagery you used to imply the baby’s death was great. …I’m a horrible person for saying that. Lol The last line also tied the story together nicely. I really enjoyed reading this; your writing style is very captivating at times. :)

-Ramen

I enjoyed reading your story very much mostly because of two important details you used. I'm a bit of a vampire buff and this often prevents me from enjoying most vampire stories. Most authors chose to use the full moon as the perfered moon phase for vampires but you chose to New Moon which is most fitting. Just curious what inspired you to chose this moon phase? The second detail was the vampire finding children's blood as being too sweet.

Writing
I really liked the way you've used the first person here. Your writing does a very good job of 'getting into character'. I loved the way you tied in the moon- very poetic. Your writing is wonderfully fluid
Enjoyment
I loved this piece! Although this is a somewhat cliched plot and subject, I like the cadences that you've used, and the way you present the entire thing. Children's blood being too sweet was an original notion, I may add.
Characters
I just LOVE the vampire! Here on FP, and sadly even in published novels these days (*cough, Twilight, cough*); vampires are either "Gimme blood!" or "I'm a monster, boo hoo!". Your's however, is effortlessly at ease with what he is, and revels in it with impunity.
Dialogue:
It isn't clear exactly what time you've used for this piece. But if I were to assume modern day, you might want to change the dialogue of the wife. It comes out as far too formal. Make it more natural. The vampire's speech is the same, although you could justify that with the whole immortality deal.

Great. I'm a total sucker for a good vampire story!

simply amazing..i do love a good horror story