Just my observation on this line of thought. It, in my opinion, doesn't matter what you call it or how you define it at all. There is no rigid "mode" you are in where you have to do it this way or that way. This is the way TFP are doing it. Not judging it as good or bad because it doesn't matter. If it doesn't fit your definition of an Alpha then so be it, agree to disagree. Don't call it and Alpha state if it makes you feel better...call it being in a "TFP State" because that defines them as working on this game in the way they do it. Part of accepting that TFP State also includes their rights to call it Alpha, because it has 0 impact on what is important...which is, they are doing it.
They could call it "Prisim Mirror mode" state and it would have 0 impact on the only part that really is important...which again...is what it is they are doing it and how. There are not guard rails in a company that wants to be creative and feel free to go off some rigid definition.
It shouldn't matter what you call it. But I am curious, and open to new ideas. Can you give me some information that explains how the title of the state should dictate what you do, as opposed to just doing what you want/need to do? I know what my opinion is but I am always open to suggestion.

Understanding how other brains work is a worthy pass time of mine.
Certainly.

I've been researching game development cycles just out of interest, and came across this.
https://en.wikipedia.org/wiki/Video_game_development#Alpha
I've since done more research to confirm if that's accurate, since wikipedia is not exactly the best source of information due to it's collaborative nature. It seems to be pretty much correct in MOST cases.
Early Access games are the outliers in that regard. So if people just said "Well they can change stuff because it's an Early Access game" I'd respond with "They CAN, but it's still a bad idea when they've been 'close to beta' since the A16 videos last year."
EDIT: Adding this because I love this description from an industry vet as well.
The various studios I've worked at have revised the names a little.
There is pre-production. There are several steps to it as well, but basically it starts with pitches and prototypes, then bigger pitches, more prototypes, proof of concept, and eventually the game idea gets accepted and funded.
Main development, which fits your description of "pre alpha". This is where most of the work gets done, and the pieces are built. There are several key events.
One of the first sought-after milestones is "first playable", where it transitions from being a bunch of non-fun pieces into something that resembles a playable game.
The next is is the "vertical slice", meaning there is something that represents all the key pieces. Usually it looks and feels terrible, but all the components are represented.
There may be some additional milestones as major features are added.
Alpha declaration often matches a milestone "feature complete". All the features that are part of the design are present, or they have been cut from the design. Features are buggy, and content is often sparse, but all the things are there and working more or less correctly.
"Content complete" happens generally at some point late in alpha.
There are many bug fixes, and lots of parts are moving.
Different studios have wildly definitions of beta so it doesn't fit the same place everywhere. Usually it happens somewhere between content complete and one of the asset locks.
Next are "audio lock" and "art lock", when these assets are no longer modified except for major bugs, allowing the other systems to stabilize. Next is usually "animation lock" and "effects lock", similarly frozen except for major bugs.
With most systems locked down, studios rename it to "finaling" the game. Only the most critical bugs and certification-breaking changes are made. Eventually there are a series of final candidate builds that are heavily tested. When one is approved it is sent on to Sony/Microsoft/Nintendo for final certification. Usually their certification groups come back with a list of things that didn't pass, although sometimes (maybe 5%) the games go through cert without issue. The changes are debated (sometimes the companies will accept certain violations) and others are fixed, and then there will be another final candidate, sometimes this goes back and forth three, four, or rarely more times, it gets expensive quick.
The one that is accept is "gold", sent to the presses, and distributed wildly. Sometimes there are bug fixes or changes that were made in case the disk wasn't accepted, but those changes aren't incorporated into the game unless there is a patch.
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