Umm 5anz... That is just flat out wrong. 😭🙏
The first dimension LITERALLY IS the x-axis. The x-axis doesn't go up and down. The 1st dimension is a space with only one direction: length.
For the 2D game, it doesn't matter if it's a top-view or side-view. It's still on the x-axis and y-axis: length and width.
The "flat out" thing is a pun, isn't it
Even if that were true, there's technically nothing stopping gravity from being on the x-axis, like in literally any game where you can switch gravity. IT EVEN SHOWS IN REAL LIFE! Walk 90 degrees around the earth, and your gravity will have rotated 90 degrees, sure it's very difficult to replicate since that is 10,000km, but my point still stands.
With that being said, this could just be an x-axis rotated 90 degrees (again, ignoring the 2d images), also, see this:
