Once Planning your SNES game has you in the right background mode, the craft is composition: deciding what each layer is for and how they stack. A SNES screen is a small stack of transparencies — a few background layers plus the sprite layer — and the art is assigning each element to the right sheet, at the right depth. This guide is those decisions; for the priority bits and registers that implement them, see SNES Graphics Programming Guide.

Give every layer a job

In Mode 1 (your usual choice) you have three background layers and the sprites. Assign roles before you draw:

Layer	Typical job
BG1 (16-colour)	the main playfield — the tiles the player interacts with
BG2 (16-colour)	a parallax midground or a second detail layer
BG3 (4-colour)	the HUD/status bar, or a far parallax backdrop
Sprites (OBJ)	anything that moves independently — player, enemies, pickups, cursor

The mistake to avoid is treating layers as "more space for tiles." Each layer is a depth, and depth is a design tool: foreground, playfield, midground, sky. Spend them on separation, not just capacity.

Depth is priority, not layer order

The powerful, non-obvious part: you interleave sprites between background layers using priority bits, so draw order is not fixed by which layer is which. A single scene can read as:

  far backdrop (BG3, low priority)
< enemies behind a pillar (sprites, low priority)
< the pillar        (BG2, high priority)
< the player        (sprites, high priority)
< the HUD           (BG3 tiles flagged high priority)

That is how you get a character walking behind a foreground column, or a HUD that always sits on top, without extra hardware layers — just priority flags on tiles and sprites. Plan your scene as a set of depths first, then assign each element a layer + priority that lands it there.

Three compositions you will reuse

Parallax — depth from motion

Scroll layers at different speeds and the eye reads distance. A far layer that creeps, a midground that keeps pace with the camera, a foreground that races past. Two ways to do it:

Per-layer scroll — simplest: give each BG its own scroll rate. See Mixed Scroll and Parallax Scrolling.
Per-scanline scroll (HDMA) — change a layer's scroll every line for smooth gradient parallax on a single layer (mountains, water). This is the SNES-specific technique the camera literature does not cover.

Go deeper. For camera movement itself — deadzones, look-ahead, room-locking — read Itay Keren's Scroll Back, the definitive taxonomy. Compose your parallax layers here; decide how the camera follows the player there.

The HUD — always on top, cheaply

Put the status bar on the layer whose priority keeps it above the action — Mode 1's BG3 is the classic home. Two routes:

Tiles with the priority bit set — a fixed HUD baked into BG3. See Mode 1 BG3 High Priority -- HUD Layer Over Backgrounds.
A 9-slice panel — bordered boxes stamped at runtime (health, dialog). See panel_hud — a HUD that survives a dialog box.

Keep the HUD out of the scrolling world: it should not move when the camera does. Give it its own layer (or a fixed region) so gameplay scroll never drags it.

Foreground occlusion — walking behind things

Flag a foreground layer (or specific tiles) high-priority so the player sprite passes behind it. Pillars, foliage, doorways, tunnel mouths — cheap depth that makes a flat tilemap feel three-dimensional. It is the same priority mechanism as the HUD, aimed the other way.

When you need more than layers can give

Four cheap layers (menus, board games, busy backdrops): drop to Mode 0 — four 4-colour layers. See Mode 0 — 4-Layer 2bpp Background. You trade colour depth for layer count.
Per-column motion on one layer (a rippling flag, heat-haze, water): offset-per-tile in Mode 2 gives every column its own scroll from a table. See mode2 — offset-per-tile: per-column scroll from BG3. This does per-*column* what HDMA parallax does per-*scanline*.

The one rule

Design the screen as depths — sky, far, playfield, foreground, HUD — then map each depth to a (layer, priority) pair. Layers are how the hardware composites; depth is what the player sees. Start from what they see.