- Knight Lore (https://news.ycombinator.com/item?id=23667891): that's isometric rather than 3D poligon. This is the problem with 3D though, it can be conflated to mean several different things:
. 1. 3D polygons: like Quake and later, and generally what we now think of as 3D rendering
. 2. Stereoscopy: like 3D cinema and the 8-bit 3D addons for the Master System / Sega Mark III (https://www.youtube.com/watch?v=S9hrcd25-kU) and Famicom (https://en.wikipedia.org/wiki/Famicom_3D_System) -- as it happens I own both of those 3D systems and they're actually pretty good for 80s tech
. 3. 3D isometric: like Sonic 3D Blast (https://www.youtube.com/watch?v=5Oon2HKYqYI) and Knight Lore.
- Sentinel (https://news.ycombinator.com/item?id=23667789): At least this game is 3D polygons however it's not a platformer. There were plenty of 3D poligon based games before Alpha Waves. I remember playing a game called Articfox on my Amstrad CPC 464 (https://www.gamesdatabase.org/game/amstrad-cpc/arcticfox) back in the late 80s and being shocked that 8-bit system with 64k of RAM had the capability to draw polygons. Even before that there were 3D maze games; going back to the CPC, Sultans Maze (https://www.youtube.com/watch?v=3x4b4k1pPRE) was released in 1983, often came bundled with the micro computer and that's not even remotely first of it's kind. None of the aforementioned are platformers however.
- I, robot (https://news.ycombinator.com/user?id=rsaarelm): While that's got platform elements, it's really more of a shooter. Games similar would be Space Harrier and Starfox. Where this game stands out is the puzzle platformer elements but they're more a mechanic of specific levels than the defining quality of the game.
So it's fair to say Alpha Waves is the first "3D platformer" but where '3D' means 'polygon' and 'platformer' is the game genre; but other '3D' games existed before.
Backlash (also for the Amiga) is also interesting, though more of a "3D shooter":
I loved this game and this might be peak Infogrames for me.
- Controls - Alpha Waves uses tank controls - left and right rotate the character rather than move them. This control style continued for many years all through the Playstation 1 period and was a fairly natural fit for digital d-pad like controls. Super Mario 64 was the first game of this type that uses direct control (left moves him left, right moves him right, etc.) and it revolutionized 3d platformer control schemes. There is a clear break with games before and after Mario 64 w/r to this style of control. I believe some modern recreations of older games (some of the Resident Evil games) now use the Mario scheme even though the originals used tank controls.
- Camera - Alpha Waves slots the camera directly behind the player with very little deviation left and right. The more dynamic camera found in later 3d platformers doesn't really exist here. The camera does rotate up and down to show different perspectives on the avatar, but IIR it's entirely up to the user to move it to where they wish. This technique is today very common and is usually mapped to the right control stick.
- Depth Perception - One of the problems with 3d platformers is that there's no depth perception since it's not stereoscopic. This makes landing jumps and gauging other movements difficult. Games try to accommodate for this reality by using several "tricks" and Alpha Wave more or less figured many of them out. The first trick is a shadow that moves directly under the avatar. This often doesn't make sense given various lighting conditions, but provides a clue as to where the avatar is at any given moment. The second trick is to dynamicall move the camera above the shoulder of the avatar which introduces a bit of parallax and assists the creation of depth. An early game which combined these was the Playstation game "Jumping Flash" which forced the camera to take a top-down view and has a shadow target under the player that made landing jumps relatively easy. Alpha Waves is interesting because instead of forcing the camera like Jumping Flash, platforms have a forced "bounce" and the user controls the camera.
It's a beautiful game that represents some really solid innovation that's totally worth at least 10 minutes of your time to check out.
Sentinel may well qualify on some definitions of 3D platform (1986): https://www.youtube.com/watch?v=9V_pgo3vgiI
Video of ALpha Waves (1990): https://www.youtube.com/watch?v=qwFPV855sI4
 'aactical' isn't a word
I think it was in his 1830/France season of revolutions (6).
What people mean is "before it was an established thing" "before parameters were known" or "after it was an established thing"
Like "tallest building" what they mean is "challenging to construct vertical structure that needed special considerations"
It's mostly used figuratively as a narrative backdrop like it is here and not as some indisputable factoid
For years, people thought Warren Robinett had made the first video game easter egg in Adventure for the 2600. Turns out there have been three other contenders for that title. The first contender was Video Whizball on the Fairchild Channel F, from 1978. 
In 2017, Ed Fries learned of the existence of an egg in the 1977 Atari arcade game Starship 1, and did the legwork to determine a more accurate release date, as well as the egg's trigger method. He dated it to August 13, 1977 (release date, so egg would have existed prior to that date while in development and production). 
Guinness even currently recognizes the Starship 1 egg as the first known video game easter egg . While this is currently the first known arcade game easter egg (therefore Ed Fries' claim is accurate), there was an even earlier egg found in Spitfire on the Channel F. Someone even found a newspaper ad claiming Spitfire was available for purchase on April 16, 1977, making it the earliest known video game easter egg. 
And with that I have spent way too much time putting together an HN comment lol
Before things get a name, culture, rules of what it is and is not, there's many instances that are close to it. Those are interesting as a collection but drawing the lines between the isolated elements can be a bit dubious. Ideas are communicative but also come out of thin air.
We have an unprecedented amount of knowledge at our fingertips these days and can cross correlate vast expanses of say, music. You can hear say some song from 1960s in peru and then see how similar it was to something in japan in the 1980s but actually showing that the second creators even knew of the first, that's the part that I think is hard - it has to be demonstrated.
Just the other week I was talking with some artist from northern england who sounded like legowelt (danny wolfers) telling him how much I really liked his legowelt-style song - danny is a minor figure generally but pretty well known in the subgenre of electronic music he works in. This guy honestly said "who's legowelt" and got back to me the next day "wow, this guy's amazing, never heard of him".
So even today, with the internet, you can have someone essentially sound like the exact style and still have never heard of the person they're supposedly "influenced" by.
It expunges the tidy narrative where we want everything to have a clear delineated beginning. "Rappers Delight began the 80s rap formula" - that one super clear, yes, hard to argue against - but most things are not so clear.
here's an example of the "legowelt imposter" https://bassagendarecordings.bandcamp.com/track/mind-to-body... who I claim sounds like https://www.youtube.com/watch?v=6BZbJY28iSM
People who write games play games and get inspired by other games they've liked. So while someone might declare something being a first in a genre, someone else might say "this earlier game is similar enough to that genre that it still counts".
It also doesn't help that 3D is such a (mis|over)used term that it can apply to a broad range of different styles that are worlds apart from one another (as I describe in more detail here: https://news.ycombinator.com/item?id=23668287)