First thing's first: thanks everyone(!) Nuclear Knights is now out, woohoo. A setting guide and adventure/arc module is also coming sometime soon, though my initial stated release date of ~March 25th is certainly not going to happen. I'll let you all know when it's ready, show the best bits as they become finalized, and so on. Anyways:

Over the course of making a big game, you (as artists often repeat) kill a lot of your darlings. There's stuff in there that rules, but just has to go. Over the many years of iteration that Nuclear Knights went through, it has ship-of-Theseused from one set of darlings to another (more game designerly) set of darlings. In no particular order, in case anyone is interested, here are some the hardest darlings I found to cut:

The OLD ONE, now relegated to an enemy in the Atomic Adversaries book, was one of the first playable classes in the first build of the game. They are vanta black floating platonic solids (polyhedral) that cannot speak besides telepathy, do not eat or sleep, and seem to be from either space or the pre-nuclear world. That was just too much to explain in any streamlined class system (like, can they wear armor? How do they hold stuff? Do they see like through invisible eyes or what? Where do their lasers come from on their shape?) Like, of course. But it was sooo sick.

The biggest changes almost all relate to a relatively late-in-development push to divorce disciplines (learned, speccable ability trees that all character have access to) and classes (set abilities and stress limits that never change or overlap). Before, a lot of classes were directly tied to disciplines because... they're where the discipline came from. Before there was Truespeak, there were Heralds, who were de facto Truespeakers at the time (now having become a sort of dedicated discipline start-class). Diviners were called Psychonauts and had access to Telekinesis. There used to a class called the Pilgrim that only used Divine Worship abilities, replaced now with the Scholar. All of those classes made a lot of sense for the particular world I was running, but as time went on, quarters were brooked for a more open ended approach to the world and mechanics. A difficult choice and a tedious change, but certainly a correct one.

The Operator class used to be the Postmaster, and they were just a mailperson. People did not often choose to play the Postmaster. I figured this might be down to the fact that the fantasy of the Postmaster was essentially to be a cog in a machine- at their best, they were someone else's means to coolness. In an effort to rectify this, they turned into the Operator, who is just the sort of person who Gets Jobs Done. They can still be a mailperson if you like, though.

"Knack" was a core stat in the first version of Nuclear Knights I ever made, when I was still in High School. It got cut mostly because A) it's not a particularly pulp fantasy idea and B) what does it mean? I mean, I love it, but what does it mean? So Knack was sent away. It'll return some day, somewhere.

A reverse-darling was that for many years, radiation was not a mechanic in any way. Initial builds of the game were all d20 and add-stat based, and there was only one bar for HP. Adding the stresses, (and radiation in particular) was a revelation for the design and flavor. Like, as soon as it was added, I couldn't imagine the game without it. I hate an HP bar (this isn't true)! Get it gone!

The original means of healing (back when there was HP) was that every character had two things called 'character beats' that would be like "find a moment to yourself in nature" or "pull off a stunt when it's dangerous to fail." These were, ideally, things the character liked doing. The idea was that this would mechanically enforce a degree of roleplaying and add some depth of thought to the characters, but it proved quickly not to be a good idea. I no longer feel the necessity to enforce roleplaying. The depth of thought sort of comes naturally, as is needed, and as a healing mechanic it was weird. Well intentioned, but it felt good to cut it off.