The comedy throughout revolves around the conceit that the vampires onstage precede Christianity and so aren't necessarily injured by the clichéd bag of tricks often bandied about by on screen Buffy's and the like (garlic, crosses, etc), leading the young hero to look foolish in his attempts to do in the vampire. Nonetheless he persists, eventually building a pentagram on stage and seemingly doing all the baddies in. One of the things that struck me about this piece is the vision, based on his historical reading and study, informing Heaney's exploration of the need for ritual on stage. There are some truly symbolist moments when the spectator feels that they are somewhere between a séance with Madame Blavatsky and the more interesting parts of Stephanie Meyer's imagination that she herself hasn't quite accessed yet. And all this very well balanced tonally, so that we go into a long and well delivered monologue by Popek that betrays her character's age (and perhaps attendance at the openings of some Beckett shows over her 2500 year life), then flip quite nicely into an ironic consideration of what has just preceded with one well delivered syllable ('So,' I think it was) by the Vampire. The longer dance sequence is similarly interesting.
If there's work to be done here it's probably in the general maturation of the actors, which will happen naturally over time, but they are at the top of their game for the level of training they have. Textually Heaney has to be careful that that same ironic reversal of tone I refer to above doesn't end up being used too frequently, or in too pronounced a fashion, as it many become slightly monotonous. Involving the audience somewhat more in the ritualized aspect (even if it is question of ackowledging our presence more throughout as they do in the pre-show) may be a way to bring this out to a larger audience as Heaney expressed that he intends to.
All in all, a rich exploration, well-performed, and the sense of a real theatrical voice beginning to emerge.