Submission guidelines can be found here. Be sure to read them if you're planning on submitting anything. The gist is that microfiction can be up to 260 words long, poetry can be up to 26 lines long, and reviews of horror media should be under 520 words long.
It is currently accepting submissions for the April 31 (Walpurgis Night) issue. Submissions close on March 31.
I'm not affiliated with them, I don't even personally know the person who puts it together. I just think it's kind of neat. I myself am planning on submitting some stuff to it, and I know there's a lot of horror and horror-inclined writers here, so it feels worth it to at least plug the zine.