gistfile1.txt

-100: Level Background
 -95: Furthest back BGOs
 -90: Sizable Blocks
 -85: Some more BGOs
 -80: Warp - Derived BGOs (locks on doors and stuff)
 -75: Background NPCs (vines, piranah plants, diggable sand, mother brain, things in MB jars)
 -70: Held NPCs
 -65: Normal Blocks
 -60: Furthest Back Effects (doors, pressed p-switches, some other stuff)
 -55: Some NPCs (i.e. coins, clown car, chompy, herb, wood rocket, koopaling fire)
 -50: Some NPCs (ice blocks)
 -45: Normal NPCs
 -40: Symbol above NPCs that want to chat (hardcoded-43/44)
 -35: Player Mounts
 -30: Something else player mount related?
 -25: Players
 -20: Foreground BGOs
 -15: Foreground NPCs
 -10: Foreground Blocks
  -5: Foreground Effects (all not at 0091DD90)
   1: Lua - Default priority for drawImage, glDraw
   2: Lua - Default priority for placeSprite
   3: Lua - Default priority for text
   5: HUD
   
NOTES:
Allowed to use values from -100 to 10 inclusive.
If you specify a value equal to the layer priority for a normal SMBX layer your Lua drawing will be above it.