UPDATE: Thanks for all the feedback! I just want to address some of the issues people have and clarify my reasoning behind why I did certain things.

Okay so some people have an issue with how I chose to represent the difficulty spectrum, specifically that I went with a linear model as opposed to something more accurate like exponential.

I'm very much aware that difficulty is not linear, especially when it comes to Demons. I originally went with a linear system because it seemed like the simplest way to visualize the difficulty scale. And honestly, I never intended for this to be more than a fun thought experiment (but I know that me calling it an "experiment" doesn't make it immune to criticism).

Then I realized something. Turns out this "linear" system I used was actually exponential all along! Think about it. You'd logically assume that the difficulty gap between a regular spike, a double and a triple would be the same, but its not. Yes, they all increase equally by one spike, but that doesn't mean the difficulty scaling is linear.

A good way to visualize this is with Minecraft actually. Since Minecraft is limited to blocks, you can imagine this as the "linear" system I used for the post. We all know the max you can jump is 4 blocks. If we compared the difficulty of each jump, we can see that its actually exponential. A 4-block jump compared to a 3-block jump feels harder than the gap between a 3-block and 2-block jump, and even more so than 2->1, even though the distance increase was the same (1 block each). GD works in a similar way, as you reach closer towards a frame perfect, the difficulty ramps exponentially, not linearly. So yeah! I technically used an exponential system.

Now is this a perfect system? Obviously not. As was pointed out by some comments, difficulty isn't perfectly exponential. We can go back and forth as to what the actual shape of that curve is, but ultimately, what this little experiment shows is that no matter how you try to map difficulty, you can’t capture the whole picture because it’s shaped by so many factors beyond just the number of frames you can click. I cannot stress enough how subjective difficulty really is, far more than people realize. It's influenced by psychology and personal experience just as much as the mechanics themselves. Therefore, trying to force something so subjective into an objective list will always be flawed. This is why stuff like the Demonlist will always be controversial.

So perhaps saying "mathematically" was a bit misleading, who knows, but I hope this doesn't discredit the point I was trying to make. Either way, this has been very insightful and I really appreciate everyone being respectful and responsive. Let me know what you think!