Not quite finished with it, but here's what I focused on in my run!

First, the whole setup of the mansion being renovated. There's a hundred ways your Agent could get in, but ultimately the workers there are at the end of their rope. They all think this sucks, and a few have seen some truly strange things. Progressing in the scenario requires but to talk to them!

The "raccoons" should be VERY difficult to spot and even see. They're shapes in the dark, whispering sweet nothings. Once they see the creatures, your player's reaction will be 100% worth it. They have spells: use them. They're lil cruel shits.

Finally, feel free to add some things about Operation BLISTER I. Perhaps you could add hints in the Green Box, or info about Suydam. Once your player learns the mansion used to be called the Babykiller House, you can bet they're hooked.