Slingshot is a pixel-art orbital arcade. You launch from Earth with a thin fuel tank, steal speed from planets with gravity assists, and try to leave the Solar System. You still do not fully know why. You just have to.
Spacify lives in the pause menu, a fake streaming player inside the game. Each successful escape destination unlocks a song, and the chrome tints to that destination colour. The first twelve tracks here are those themes: Sagittarius A* is Gone Forever, Andromeda is Empty Space, Orion is Exploring Space, Cassiopeia A is Into the Nothingness, Cygnus X-1 is Void, Antares is Nothing to Chaos, Vega is Missing Earth, Polaris is Alone in the Universe, Pegasus 51b is Perihelion, Proxima Centauri is Deep Space Exploration, Ursa Major is The Weight of Dawn. Aquarius keeps Gravity Lives Here in the game only.
Gone Forever (vocal) belongs to the Lone Probe, a cartographer easter egg and the only song with a human voice. Blue Shift, Come Closer, Space Groove, Interstellar, Hyperspace, Hinterlight, Mass Driver, Signal at Dusk, and the other vocals are extra music written around the same escape.