Great scenario concept, the classic underwater research base full of biological threats. Well executed. The document looks clean and is easily readable. After reading it once, you can tell at a glance what section a page belongs to by it's layout, which is a clever idea. Each layout used works well, which is no small feat. Really impressive offering!
I wouldn't allow the Janus Bio Pistol in my game. Elevating a PbtA-style roll up a tier every time a particular weapon is used promises to be a game breaker. As a player I'd take it over a bandolier of 4d6+4 handgernukes. The rest of the unique items and the Janus M quasi-Traits are pretty cool though!