Captain Callisto Platformer — an honest story about a game that owns your evening

Sometimes the simplest-looking game hooks you harder than a blockbuster. This is exactly that case: the rules take a minute to learn, and putting it down is much harder.

What this game is

Captain Callisto — a 3D WebGL2 space platformer by Cody Ebberson, built for js13kgames 2021. Despite fitting into 13 kilobytes it renders volumetric shadows, bloom glow and depth-of-field post-processing. You play an interstellar adventurer on the planet Zeta, progressing through 10 levels from your landed ship up to the tomb of the giant boss Kang. Each level's goal is to collect EVERY scattered treasure and only then reach the transporter flag — the flag only triggers once all coins are gone. Enemies and turrets fly between the platforms, moving lifts carry you up, and a jetpack (fuel is limited) saves you from a bad jump. The whole world, music ("Milky Way" from FTL by Ben Prunty) and sound (ZzFX synthesizer) are generated in code.

How to play, in short

1. Captain Callisto — a 3D WebGL2 space platformer by Cody Ebberson, built for js13kgames 2021.

2. Despite fitting into 13 kilobytes it renders volumetric shadows, bloom glow and depth-of-field post-processing.

3. You play an interstellar adventurer on the planet Zeta, progressing through 10 levels from your landed ship up to the tomb of the giant boss Kang.

4. Each level's goal is to collect EVERY scattered treasure and only then reach the transporter flag — the flag only triggers once all coins are gone.

5. Enemies and turrets fly between the platforms, moving lifts carry you up, and a jetpack (fuel is limited) saves you from a bad jump.

6. The whole world, music ("Milky Way" from FTL by Ben Prunty) and sound (ZzFX synthesizer) are generated in code.

Controls

Controls: run — arrows or WASD, jump — Z or space, jetpack — X or Shift (needs fuel), restart level — R, toggle music — M, main menu — Esc. Score — the highest level you reached; reaching the credits after the final boss counts as a win. On phones the whole set is duplicated by an on-screen d-pad plus jump / jetpack / continue buttons.

A few final tips

• Check out the demo mode on the game page — the AI shows how it is played, and repeating it yourself gets much easier.
• Play in short sessions: the best results come with a warmed-up head.

Simple on the surface, deep underneath — exactly the kind of game that never ages. Ready to try? "Captain Callisto Platformer"