Only One door

Level 1

Inspiration

The idea struck me while watching adventure films where the ground gives way at any moment. I wanted to recreate that heart-in-your-throat tension in a simple 2D platformer—every step could be your last until you reach the only door out.

What it does

Only One Door challenges players to traverse a series of fragile platforms. As you approach gaps, the ground slides away; step on the wrong spot and a hidden pit opens beneath you. The goal is to reach the lone exit door in each level without falling.

How we built it

Engine: Godot 4.x
Scene setup: A Node2D root with Ground nodes, Player (CharacterBody2D), and three Area2D triggers (GapTrigger, HoleTrigger, DoorTrigger).
Smooth animations: Used SceneTreeTween to slide platforms away when GapTrigger fires.
Precision pits: Split one CollisionShape2D into three shapes (full, left, right) and swap them in HoleTrigger callback with set_deferred() to carve out a safe hole.
Respawn & transitions: Player fall-limit triggers get_tree().reload_current_scene(), and reaching the door calls change_scene_to(next_scene).

Challenges we ran into

Collision hiccups: Directly disabling a collision shape in the physics callback kept the player stuck in mid-air. We solved it by deferring the disable call.
Trigger timing: Getting the gap to slide at just the right moment required iterative tweaks to trigger area positions and adding small code delays.
Scene management: Ensuring smooth respawns and door transitions without frame drops led us to streamline scene reloads and preload the next level.

Accomplishments that we’re proud of

A fully modular Level.gd that cleanly handles three distinct triggers (gap, hole, door).
Robust deferred collision swapping for realistic pit openings without any physics glitches.
Seamless scene transitions and reliable instant respawn on falls, creating a tight, responsive gameplay loop.

What we learned

Mastery of Godot’s SceneTreeTween and chainable tween API.
Why and how to use set_deferred() when modifying physics properties mid-frame.
Best practices for signal-driven architecture in 2D platformers.
Managing multiple levels via change_scene_to() and exportable PackedScene properties.

What’s next for Only One Door

Add new trap types: moving platforms, timed spikes, rotating blades.
Implement a fade-out/fade-in transition tween for even smoother level changes.
Design an “endless mode” with procedural level generation and a global high-score board.
Polish mobile controls and touch-friendly UI for a wider audience.