Trophy Loom is a setting book. It’s not required; just like you don’t need a Forgotten Realms or Dragonlance book to play D&D 5e.
Trophy Dark is a system for one-shots. The book includes a bunch of adventures. The PCs are expected to be irrevocably changed, “lost” to the horrors of the world, or dead by the end of the session.
Trophy Gold is for campaign style play. The PCs are more likely to survive and return to town at the end of a session. There’s a few more mechanics than Dark, but both are rules-lite. The book comes with a few adventures.
The tone and genre for both games (and the setting book) is dark, gritty, dangerous low-magic, late-medieval/early-renaissance fantasy.
Edit to add a content warning: horror is a main theme. And body horror is a big part of many of published adventures.
I had a DM wanting us to come up with a party name after a dozen or so sessions together. Our first big quest - and a couple reoccurring themes - had to do with escorting NPCs, so we decided to call ourselves “The Escorts”. All the players not only liked it but were actually excited about it. But DM flat out refused to allow it. (Important context, we were all adults between 25 and 40). We never came up with another name, and the campaign started falling apart no long after that.