Count Echula

A cute-spooky rhythm runner made with Rive, and my entry for the Rive Halloween Challenge 2026.

On Halloween night, Count Echula (a vampire turned into a small bat wearing oversized headphones) flies down a trick-or-treat street that's invisible in the dark. He can only see by echolocation, and his sonar only fires on the beat. Catch the candy that sits on the music to send out sonar pulses that light up the street. Dodge the garlic and wooden stakes you can't see, and grab as much candy as you can before the song ends.

Echula = echo + Dracula.

Play it in your browser. It works best on a phone.

Screenshots

How to play

Gesture	Keys	Action
Swipe left / right	← / → or A / D	Change lane. Swipe into a candy's lane on its beat to catch it (PERFECT / GOOD)
Swipe on the title screen	← / →	Pick a record
Tap on the title / results screen	Enter	Play / retry (the first tap also turns on the sound)
Pause button (top right)	Esc / P	Pause: resume or go back to the record shelf

Each candy you catch fires the sonar on the beat and shows the next stretch of the street before the fog closes in again. Catching candy is the only way to see: if you miss one, you're flying blind.

Three records to pick from:

• Side A, Echula Theme: the easy one, with a foggy bridge.
• Side B, Funky Counting: disco-funk with a "Cold Moon" breakdown that freezes the street.
• Side C, Werewolf Wipeout: surf-rock with a blackout, then the street keeps speeding up until the last hit.

Built with

• Rive CLI: the scene, HUD, title and results screens are written in Rive Markup Language (RML)
• GPU Canvas: WGSL shaders for the sonar outlines, fog, night sky and glitch effects (game/shaders/)
• Scripting: game logic in Luau, including the beat clock, beatmap, gestures and rules (game/world.luau, game/lib/)
• Data Binding and State Machines: they drive the HUD and the title → play → results flow
• Audio: the songs play through Rive Audio, and a beat clock reads their position so the street, candy and sonar stay on the beat. Sound effects and the music-box catch notes are synthesized (scripts/make_sfx.py)
• Rive Editor: Echula's front view and salute were drawn and animated by hand in the Editor, then pulled back into the CLI project (game/echula_front.rml)

Run it locally

The repo includes a prebuilt game file (game/build/count-echula.riv). To play it in your browser, serve the repo root with any static server:

python3 -m http.server 8000

Then open http://localhost:8000/web/.

The page (web/) runs the game with the Rive web runtime and adds a few things the game file can't do by itself:

• portrait stage, letterboxed on desktop with a haunted street backdrop
• multi-touch input, so a lost touch on iPhone never locks the controls
• audio unlocked on every tap (iOS only starts sound inside a user gesture)
• the game pauses when the page goes to the background or a phone turns sideways, and comes back on its pause menu

Rebuild from source

You need the Rive CLI.

rive game --verify    # check that the project compiles
rive game --test      # run the logic tests
scripts/web-dev.sh    # build game/build/count-echula.riv and serve it on your LAN

Project layout

game/       Rive CLI project: RML scene, Luau scripts, WGSL shaders, art, audio and fonts
svg/        Source drawings, converted into Rive artboards by scripts/svg2rml.py
web/        Small web page that loads the .riv (plus anonymous play stats when hosted)
deploy/     Hosted test build: Caddy for the page, a small Python api for the play stats
scripts/    Build + serve helper, SVG → RML converter, house and castle cut-out tools,
            sound effect synth, deploy and screen recording helpers

Credits

Game design, code and art direction by @jessaimaya.

Music: three songs generated on yueai.ai with YuE2 (M-A-P / HKUST). #YuE2

Fonts: Creepster and Fredoka, both under the SIL Open Font License (see game/assets/fonts/).

#rivehalloweenchallenge