I'm usually a huge fan of the standalone Delta Green scenarios, but this one didn't quite work for me. Don't get me wrong, there's things about it that I like: the inciting mystery is really compelling and I like the idea of the Agents investigating a weird cult (it reminds me a lot of that one X-files episode). And without going into spoilers, there's some intriguing possibilites for some interesting role playing stuff that could happen.
Unfortunately my biggest problem with this scenario is that I just don't find the cult itself to be a very interesting adversary for the Agents. They have a lot of weird rituals and beliefs and practices, and there is some creepy stuff that might happen, depending on your players' choices, but I have a feeling that most of the time this scenario is just going to devolve into "Agents find cult, Agents investigate cult, cult finds out about Agents, Agents shoot cultists"
Like I said, the cult itself has some interesting stuff going on, but I don't really feel like any of this interesting stuff really contributes to the overall scenario and/or player experience in a meaningful way. If you've already played a lot of other DG scenarios, maybe pick this one up just to check it out and see if you like it more than I did; it's definitely at least worth reading through. But if you're a newer Handler looking for a DG scenario, I'd start elsewhere.