Free Side-Scrolling Game Writing Tools for Mac: Narrative Design & Scripting

No tool is exclusively for "side-scrolling game writing," but these free/cheap Mac apps excel at narrative design, scripting, and worldbuilding:

Free & Open Source

• Twine 2 (Browser / Electron App): Interactive fiction / branching narrative. Visual node map. Exports HTML. Perfect for dialogue trees, quest logic, choose-your-path. twinery.org
• Manuscript (GitHub): Markdown-based novel/project manager. Outline, scenes, characters, tags. Export to DOCX/PDF/HTML.
• Obsidian (Free Personal): Markdown knowledge base. Canvas for visual plotting, Dataview for queries, Kanban for tasks. Plugins for timeline, outliner, script format. obsidian.md
• VS Code + Markdown / YAML: Dev-friendly. Extensions: Markdown All in One, Ink (for Inkle scripting), YAML for data.
• Godot Engine (Scripting): Write GDScript directly in engine; side-scroller template exists. Not a writing tool per se, but integrates script + scene.

Free Tier / Trial (Paid Core)

• Scrivener 3 (30-day actual-use trial): Gold standard for long-form. Corkboard, outliner, split view, compile to any format. $59.99 after.
• Ulysses (14-day trial, then subscription): Beautiful Markdown library, sheets, groups, export. $5.99/mo or $39.99/yr.
• Plottr (30-day trial): Visual timeline, character bible, scene cards, outline. $25/yr or $99 lifetime. plottr.com
• Campfire Write (Free tier limited): Worldbuilding wiki, timeline, character sheets, map. Web-based.
• World Anvil (Free tier limited): RPG-focused worldbuilding (articles, maps, timelines, secrets).

Screenplay Format (If Needed)

• WriterDuet (Free tier: 3 scripts): Real-time collab, industry format, beat board.
• Kit Scenarist (Free, open source): Final Draft compatible, cards, stats.
• Fade In (Free demo, $79.95): Pro screenwriting, Mac native.

Recommendation

Start with Obsidian + Twine. Free, local-first, extensible, covers worldbuilding, branching dialogue, and export. Migrate to Scrivener/Plottr if project scales.