script.js, ll. 57ff.

    fillRect() {
        var sideColor = this.on_side_one ? this.c_side_1 : this.c_side_2;
        ctx.fillStyle = sideColor;
        ctx.fillRect(g_pixelOffset + (g_pixelOffset * this.x), g_pixelOffset + (g_pixelOffset * this.y), this.radius, this.radius);
    }

All these computations don’t have to be delayed until you’re actually drawing the dot. If you’d compute them when you’re creating the dot, the rendering might become smoother.

Use requestAnimationFrame for the drawing loop. Dont instantiate new objects unless needed

You’re mixing spaces and tabs for indentation. This makes it hard to read for anyone whose tab settings aren’t the same as yours.

With all these comments said, I experience no problems in Firefox on Linux, and I really like the art style. If one browser is troublesome to you, check which function(s) really are the culprit. (This is actually true for any optimization: Only optimize the stuff that’s slow (duh)).

First: For every performance optimization you do, you must actually measure if it improves things. It could be that you’re doing a perfectly sensible optimization, which turns out to work against the compiler (yes, even JavaScript is compiled) and thus decreases performance.

In script.js, l.149ff:

	drawImage(Image, topLeftX, topLeftY) {
		for (let row = 0; row < Image.length; row++) {
			for(let column = 0; column < Image[row].length; column++) {
				this.nextFrame[(topLeftX + column)*this.height + (topLeftY+row)] = Image[row][column];
			}
		}
	}

The term topLeftX + column * this.height can be rewritten as topLeftX * this.height + column * this.height. The first term of this is a constant and can be extracted into a variable const verticalOffset = topLeftX * this.height.

Similarly, topLeftY + row doesn’t need to be recomputed in every iteration of the inner for loop. Move it out into the outer for loop.

Also notice that the variable part, column * this.height is all the integer multiples of this.height. Therefore, instead of a multiplication, you can simply add this.height to a running total. Sums should be faster than multiplications.

With these three changes you get [Edit: I think I made mistakes during the replacements.]

drawImage(Image, topLeftX, topLeftY) {
	const TODO_NAME_THIS = topLeftX * this.height
	let TODO_NAME_THIS_ALSO = topLeftY
	for (let row = 0; row < Image.length; row++) {
		let TODO_NAME_THIS_TOO = 0
		for(let column = 0; column < Image[row].length; column++) {
			this.nextFrame[TODO_NAME_THIS + TODO_NAME_THIS_TOO + TODO_NAMES_THIS_ALSO] = Image[row][column];
			TODO_NAME_THIS_TOO += this.height
		}
		TODO_NAME_THIS_ALSO += row
	}
}

script.js, ll. 788ff.

for (var i = 0; i < elements.length; i++)

If you’re not using the index of an iteration, you might as well use the array iterator. This is more of a legibility improvement rather than a performance improvement.

for (const element of elements)

A random suggestion would be to draw to multiple canvases, and use a CSS animation for the delay.

Also not sure if you are already doing this but it might be more peformant to use the raw buffer instead of draw functions.

Alternatively you could look into webgpu, it is ment for these kind of things.