I ran this for a few friends last week, and it was loads of fun! word to the wise for GMs: you may want to prepare a little bit for what the ritual will look like ahead of time. that stalled things a bit at the start, but I ended up just asking each player to tell me one thing their player knows about the ritual, and went from there. otherwise, fully improving it went fine
in the end, two of my players tried to kill each other to earn the Horror's love, and by spending all their favour to lower each other to zero successes, killed each other at the same time. the third "won" by default, and everyone was happy with their characters' endings.
one told me later it was the most fun they'd had in a while!