PROJECT PLANETFALL

A jetpack-powered platforming adventure where players create, share, and conquer challenges on a dangerous alien world.

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Inspiration

We grew up on games like Jetpack Joyride and classic 2D platformers, and we loved the idea of bringing that "one more try" feeling directly into a Reddit feed — no downloads, no app store, just a post you can play. Reddit's community DNA inspired the bigger idea: what if the community built the levels? Planetfall started as a simple jetpack game and grew into a player-driven level-sharing platform that lives entirely inside Reddit.

What it does

Project Planetfall is a 2D jetpack platformer that runs inside a Reddit post. You guide a stranded astronaut through hazard-filled space stations — managing limited jetpack fuel, dodging lasers, spinning blades, contact mines, crusher pistons, homing missiles, steam vents, and gravity wells that pull you past their event horizon — collecting stars on the way to the extraction pad.

  • Play — Handcrafted levels with a 3-star scoring system (speed + full star collection), playable on desktop and mobile (virtual joystick).
  • Create — A full WYSIWYG level editor built into the game: paint terrain, place and configure hazards, set star rules, then publish your level as a brand-new Reddit post for anyone to play.
  • Compete — A Daily Challenge: a deterministic level stitched from curated chunks, the same for everyone each day, with a Redis-backed leaderboard.
  • Share — Finish a run and the game can comment your result on the post as you, turning every level into a comment-thread competition.

How we built it

  • Phaser 3 (WebGL) for the game engine — arcade physics, sprite atlas character animation, parallax backdrops, and a cinematic intro flyover that sweeps from the goal back to your spawn.
  • React + TypeScript + Vite for the shell, HUD, menus, and the level editor UI.
  • Devvit Web for the Reddit platform layer: an Express server handles level publishing, daily-challenge seeds, and leaderboards, with Redis storing published levels and daily scores (sorted sets for rankings).
  • Reddit API with runAs: USER so score comments post as the actual player.
  • Web Audio API for a hybrid audio system: a procedural SFX synthesizer for UI and game events, plus file-backed loops (black hole rumble, electric spark, laser hum) with positional audio — hazards get distance attenuation and stereo panning, so you can hear a crusher piston before you see it.
  • We even built internal tooling: a "Backdrop Forge" for composing parallax backgrounds, and chunk-based deterministic generation for the daily level so every player worldwide gets the identical challenge.

Challenges we ran into

  • Mobile performance. Post-processing glow effects and unthrottled particle emitters on lasers tanked the frame rate on phones with just two lasers on screen. We rebuilt the laser rendering to be cheap-by-default and throttled particles.
  • The Devvit webview lifecycle. Going from an inline post preview to fullscreen gameplay, and carrying state (like which community level you picked) through that expansion on mobile, took real debugging.
  • Physics edge cases. Phaser Arcade bodies don't scale the way you'd expect with sprite scale, players snagged on invisible tile seams, and auto step-climbing kept popping the fall animation — each needed careful fixes.
  • Determinism for the Daily. Making sure every player gets a byte-identical level from the same seed, while still being able to version and update the chunk pool without breaking past leaderboards.

Accomplishments that we're proud of

  • A complete creation loop inside Reddit: play → build in the in-game editor → publish as a real Reddit post → others play and comment their scores. The subreddit itself becomes the level browser.
  • Nine distinct, configurable hazard types that combine into genuinely interesting level design.
  • A game that feels cinematic for a Reddit post — intro flyovers, parallax space vistas, prize-style collect effects, and positional audio.
  • Smooth gameplay on mobile, where most Reddit users actually are.

What we learned

  • Designing for Reddit is different from designing a standalone game — the post, the comments, and the subreddit are part of the game loop, and leaning into that (score comments, community levels, daily posts) is where the magic is.
  • Mobile WebGL performance budgets are unforgiving; profile early, on real phones.
  • Redis sorted sets are a perfect fit for daily leaderboards, and deterministic seeded generation beats storing generated content.
  • Building your own tools (level editor, backdrop composer) pays for itself many times over in content velocity.

What's next for PROJECT PLANETFALL

  • Community spotlights — featured/trending player levels and weekly build themes.
  • New mechanics — the groundwork is laid for energy cells as a gameplay resource (fuel pickups, powered doors), plus new hazards and biomes.
  • Deeper social play — ghost replays of friends' daily runs, level ratings, and creator profiles.
  • Seasonal dailies — streaks, badges, and flair rewards for top daily finishers.
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