I'm wondering if this makes any actual sense.
Context matters. A lot.
You are not saying who wants to build a game, what type of game, what the scope is, if there are investors, if it is a hobby game, established franchise, experienced developers and so on. All these and a lot more will change the context.
If you invent something new, you need a prototype as a proof of concept, before you commit resources. Lest you find out that your free energy device will not ever work. A thing you might have found out by applying common sense and laws of physics. But creating software for people to have fun with is not exactly hard physics.
So you might want to recheck the target audience of those videos.
Also, some people just call their pre-alpha version a "prototype". Or do not bother at all to use classic alpha beta release naming conventions.