2D Platformer - Core (Make game skill)

Part of the make-game skill. The skill links here when your agent needs the detail.

Side-scrolling platformer blueprint: architecture, the level, and the core loop. Movement itself lives in the character-movement skill (base controller) and its platformer-feel reference (summer_docs_read id skill/character-movement/references/platformer-feel.md: coyote time, jump buffer, variable height) - do not rewrite it here; wire it in. For Celeste-grade precision movement (dash, wall jump, climb) use celeste-momentum-platforming instead.

Minimum playable base (build this first)

Scene first (the make-game Scaffold phase): main.tscn with a Node2D root, a ground StaticBody2D with a CollisionShape2D, the player, and a Camera2D child of the player. Prove run + jump + land before anything else. Placeholder art is a colored ColorRect/Sprite2D.

Architecture (grows into a full game)

res://
  scenes/
    player/player.tscn
    rooms/room_01.tscn        # one .tscn per room/level
    enemies/patrol_enemy.tscn
    ui/{hud,pause_menu,main_menu,game_over}.tscn
  scripts/
    autoloads/
      event_bus.gd            # global signals, decouples systems
      game_manager.gd         # score, lives, current room, checkpoint
      audio_manager.gd        # pooled SFX + music
      save_manager.gd
    player/player_controller.gd
    systems/{coin,checkpoint,killzone,moving_platform,one_way_platform,
             crumbling_platform,bounce_pad,door,level_end}.gd

Add autoloads only once the base loop works. Register in Project Settings in dependency order: EventBus first (others reference it), then GameManager, then the rest. All autoloads process_mode = ALWAYS so they survive pause.

Collision layers (set names in Project Settings)

Layer	Name	Used by
1	World	TileMap, static platforms
2	Player	Player body
3	Enemies	Enemy bodies
4	PlayerHitbox	Sword/stomp hit area
5	EnemyHitbox	Enemy hit area
6	PlayerHurtbox	Player hurt area
7	EnemyHurtbox	Enemy hurt area
8	Collectibles	Coins, gems
9	Triggers	Doors, killzones, checkpoints

Hitboxes mask the OPPOSING hurtbox (see the combat-basics skill). The stomp detector is a separate Area under the player masking only the Enemies layer.

Building the level with a TileMap

Use a TileMapLayer for the solid world. Create a TileSet, paint the collision polygon on the solid tiles, put the layer on the World collision layer. The player collides with it for free - no per-tile StaticBody.

One TileMapLayer for collidable terrain, a second (no collision, lower z-index) for background decoration.
For large levels, split into room .tscns and load the current room via a RoomManager; connect doors to change_scene_to_file or swap room instances.
Parallax background: Parallax2D (or ParallaxBackground) layers with motion_scale < 1 so distant layers move slower.

Moving, one-way, and crumbling platforms

These three cover most platformer level tech.

# moving_platform.gd - AnimatableBody2D so riders move with it
extends AnimatableBody2D
@export var offset: Vector2 = Vector2(200, 0)
@export var duration: float = 2.0
func _ready() -> void:
	var t := create_tween().set_loops().set_trans(Tween.TRANS_SINE)
	t.tween_property(self, "position", position + offset, duration)
	t.tween_property(self, "position", position, duration)

Use AnimatableBody2D (not StaticBody2D) for movers - it carries the player. For one-way platforms, enable one_way_collision on the platform’s CollisionShape2D so the player jumps up through and lands on top. Crumbling platform: on body_entered, start a short timer, shake, then disable collision and fade out; re-enable after a respawn delay.

Checkpoints and death

# checkpoint.gd
extends Area2D
func _ready() -> void:
	body_entered.connect(func(b):
		if b.is_in_group("player"):
			GameManager.checkpoint = global_position)

# killzone.gd - fall/spike death
extends Area2D
func _ready() -> void:
	body_entered.connect(func(b):
		if b.is_in_group("player"):
			b.die())   # player respawns at GameManager.checkpoint

Core loop checklist (the 30-second bar)

Run + jump feels good (tuned gravity/fall multiplier, coyote + buffer).
Coins/goal give immediate feedback: sound + pop tween + counter tick.
Death is instant and respawns at the last checkpoint, no long reload.
A visible goal (flag/door) ends the level with a clear result.

Enemies, hazards, juice, and metroidvania progression are in 2d-platformer-polish.md.

Source: library/skills/make-game/references/2d-platformer.md, rendered from summer-engine@4.3.0 on npm.

Overview

2D art

3D models

Agent workflow

AI and NPCs

Animation

Asset pipeline

Audio

Character controllers

Publishing and growth

Debugging

Deployment

Editor

Gameplay

Level design

Multiplayer

Navigation

Performance

Rendering and lighting

Runtime

Scenes and project

Scripting

Tools

UI

Visual effects

Video

2D Platformer - Core (Make game skill)

Minimum playable base (build this first)

Architecture (grows into a full game)

Collision layers (set names in Project Settings)

Building the level with a TileMap

Moving, one-way, and crumbling platforms

Checkpoints and death

Core loop checklist (the 30-second bar)

​Minimum playable base (build this first)

​Architecture (grows into a full game)

​Collision layers (set names in Project Settings)

​Building the level with a TileMap

​Moving, one-way, and crumbling platforms

​Checkpoints and death

​Core loop checklist (the 30-second bar)

Minimum playable base (build this first)

Architecture (grows into a full game)

Collision layers (set names in Project Settings)

Building the level with a TileMap

Moving, one-way, and crumbling platforms

Checkpoints and death

Core loop checklist (the 30-second bar)