[Tyhm]

...SUCH AS FLOATING POINT LAYERS!

Then you can have a floor tile, it's layer 0.
Then a mouse running across the floor tile, it's layer 0.1
Then an ant running under the mouse, that'd be layer 0.05
Then a cat chasing the mouse, he can be layer 0.2
Then a dog chasing the cat, layer 0.3...

You see where I'm going with this? The dog is always above the Drawunderplayer layer, but below the Player layer - and Y Ordering doesn't apply to ANY of these NPCs, as they all are on their own layers!!!

That would make my job soo much easier....

Yours too. You want it to go off index instead of y? Easy.
for(this.i=0;this.i<100;this.i++){
showimg this.i,frog.png,random(0,62),random(0,62);
changeimgvis this.i,this.i/100;
}
You get 100 frogs all over the place, each on layers determined by index instead of y. Frogs with lower y values but higher indices are drawn over frogs with higher y values and lower indices.
At least tell me I'm making sense here...