Man, this is serious in medias res. My only real concern is that this adventure seems to have only has two endings: Big win or colossal failure (probably a TPK). Many players are probably fine with this, some might not be. The linearity is a double-edged sword. Otherwise, the kitchen sink approach of stat blocks and tactical combat should be fun for an appropriately-levelled party wanting a cinematic experience. The mythic, monstrous tone is spot on for both your assigned title and the legacy of Appendix N. The art also ties everything together quite well.
Viewing post in Clash of Leviathans jam comments
Thank you! I also worried a bit about the binary-ness of it, but I figure for a one-shot it just ratchets up the tension. I’d be more wary of throwing this in the middle of a long-term campaign, but a TPK at the end of the night when you’ll never see those characters again anyway is a little less heartbreaking.