10 years ago around this season, my brother had me play a very early prototype of a little game about rockets. It was an idea both of us shared back in university, from which we had graduated just the previous year.
He had just been given a chance to make it, having threatened to quit his job thus causing his boss to offer him the opportunity to do so while under their pay. Squad had been a company for electronic media and advertisement stuff up until then.
To this event, I recall my reply was "Hey! I was gonna make that one!" - With the idea for that game just as much mine as it was his at that time, and I even actually had a working prototype.
I had just myself made a Flash-for-Mobile game like this, called "Delta Vee". It was required work for me to complete a pending class for my own graduation, and this had had the feature of allowing one to reach orbital velocity (a setup which required me to work physics inside out to achieve in limited 2d Flash)
I still have that game, and if you can get Flash to work on your PC, you can even play it: https://drive.google.com/file/d/1wTqgzMCL0X3HfSQn9fKyOBoAM1fuNnOU/view?usp=sharing
You can play DeltaVee.Swf with a program such as this freeware Swf Player: http://www.swffileplayer.com/
Anyways, that was back in 2010. By 2011 (ten years ago today-ish) my brother had his prototype mostly underway.
So, after a brief play with this first take on implementing his version of our idea, I convinced him that the casual "how-high-can-you-go-before-explosion" challenge would be more fun if instead of having only 2D physics, it should allow full 3D flight, and even getting into orbit should one manage it. It already had 3D graphics, so why not?
When I made mine, I was limited to 2D by the Flash platform. He was using Unity, so really making it work as if it were 2D was not just unneccessary, but also far more trouble than just allowing it to go as these things do in three dimensions.
He had kinda thought of this himself, yet had all but ruled it out, concerned about how difficult it would be to properly control the ship while looking at it from the outside. Plus, all that stuff about axial tilts and orbital planes made things a bit too complex for comfort.
For this, I suggested that he add a feature which has since become known as the "Nav-Ball"
I also put forward that the whole process would be far more approachable (compared to Orbiter, our shared source of spaceflight understanding) if the launch center was located at the exact equator of a miniature planet, with zero axial tilt to the ecliptic. Very much simplifying the concept of how orbits naturally work without having to cut back on physics by artificial means to that end.
And why not, if someone manages to actually fly up into orbit, let them get on with it. If the point is to go as far as possible before inevitable disaster, then why not let it go as far as possibly succeeding with a mission?
Anyways, what resulted from that bit of advice I gave should be quite self-evident to anyone who's found his way into these forums.
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Sadly, I never got any official credit for that (IMHO) critical bit of advisory. Or even any acknowledgement for having come up with Kerbals in the first place, back when they were little tin-foil men strapped to cardboard model rockets of most inadvisable repute.
Perhaps KSP2 could remedy this by featuring the "Based on characters created by:" entry on its credits roll. This time with BOTH brothers' names on it.
Would be nice if they did. Though I do hate having to ask for it...