Cool Panic Engine thing! Limit instead of Stress, and the player can pick to Limit Break (good) vs Breakdown (short-term bad, like Panic, but long-term allows for progression and growth). It's a neat way to handle horror/stress in a way that gives players a smidge more control. The bones of the system still make violence very dangerous and leaves lots of fun anti-canon things to figure out implied things. 'Each skill above the 5th Avatars take +10% chance of chrysalis split.' And what emerges?
Comes with an adventure, and Chris has written many other PWYW ones, which is awesome. Could convert other Mothership modules as well, just have to figure out how to layer in the sort of decentralized drift of human clades across vast time.