Straight lines, round orbits

What the name means

An apsis is a point in an orbit where the orbiting body is nearest to, or farthest from, the body it goes around. The nearest point is the periapsis and the farthest is the apoapsis, and together they are the apsides. Around the Sun they are called perihelion and aphelion, and around the Earth, perigee and apogee.

The game is a small planetary system: a warm sun, a few faint orbits, and arrows resting on them. Each arrow is waiting for its moment to leave, and the name is a nod to the astronomy that inspired the look.

Why we made it

Arrow puzzles, where you tap arrows off a grid, each one only once its way is clear, are one of the simplest good ideas in puzzle games. Apsis puts that idea on a circle. Straight paths cut across curved orbits, so which arrow is in whose way has to be read, not counted along a row.

We wanted a game that respects your time and attention. No energy bars, no countdowns, nothing that interrupts a puzzle. Three hearts, a quiet sky, and a moment of "oh, that one can go."

How it is built

Every level is generated by a program that builds it backwards: it adds arrows one at a time, and only ever places an arrow whose own path is clear of everything already there. Taking them away newest first always works, so every level can be cleared by construction. A solver then measures how hard each level is, the levels are ordered so none is easier than the one before, and no two levels are near-copies of each other, even turned or mirrored. The tests check all of that again on every build.

A flight is exact geometry, not a physics simulation, so what the player sees, what the solver computes and what the generator builds always agree. The art, the sounds and the music are made in code, not bought or downloaded. The game is written in GDScript with the Godot Engine, and the same code runs on Android and in your browser.

How it stays free

Apsis is free, on Android and in your browser. The Android app has a few ads, placed so they never touch a puzzle: a banner at the bottom of the level list and below the sky, an occasional ad between levels once you have solved the first dozen, and a short video you can choose to watch for an extra hint. Nothing ever appears over the sky, no full-screen ad interrupts a level, and the web version never shows ads.

If you would rather play without them, the Supporter pack is a one-time purchase in the app. It turns the ads off for good, makes every hint free, and helps pay for the next game.