Sub-Terr8nia

About the game

Sub-Terr8nia is a cave lander. Your little craft starts near the top of a deep, narrow cavern and has to reach a landing pad somewhere below. Gravity is always pulling, and the only way to fight it is the thruster, which pushes the ship in whatever direction its nose is pointing. Turn, burn, drift, correct: getting down without picking up too much speed is most of the game.

Each cave may hold a few orbs, and the pad only accepts you once all of them have been collected. The ship also has to land upright and slowly. Scraping a wall at low speed just slows you down, but a hard knock damages the hull, and the fourth one destroys it. Thrust uses fuel, shown by the bar along the edge of the screen, and some caves have fuel cells tucked into awkward corners to top it up.

There are nine caves. After the last one, the game totals your bonuses: points for every cave cleared at the first attempt, for every cave cleared without a scratch, and for the fuel you had left.

Playing it here

Sub-Terr8nia is a CHIP-8 program. CHIP-8 is a simple virtual machine from 1977, created for hobby computers like the COSMAC VIP, and people still write new games for it. This one targets SUPER-CHIP, the later extension with a sharper 128 by 64 screen, and was made for Octojam 4, the fourth edition of a yearly CHIP-8 game jam. It is designed to be played sideways, so the emulator turns the picture a quarter turn and the caves appear tall and narrow. It runs here in the Octo emulator, with the speed, colours and rotation chosen for it in the archive.

Click Play and press any key on the title. F2 saves the state of the emulator at any moment and F4 brings it back, which is handy before a tricky descent. A gamepad works too: the D-pad thrusts (up and down) and turns (left and right).

Controls

A few things worth knowing

Short bursts beat long burns. The ship keeps all the speed you give it. Tap the thruster to slow your fall and let gravity do the rest, rather than holding it down and then fighting to stop.

Land straight. The pad only counts a landing when the ship is level and slow. Turn upright well before you get there, so the last moments are spent easing off speed rather than correcting the angle.

Orbs first, pad second. Touching down with an orb still in the cave does nothing, so sweep the cave before heading for the pad. Fuel cells along the way are worth the detour.

R costs you a bonus. Restarting a cave, by hand or after a crash, gives up the first-attempt bonus for that cave, but sometimes a clean second run is worth more than a battered first one.

Credits and licence

Sub-Terr8nia was created by the developer who goes by "your name here", who wrote the code, the physics and the caves. It runs here in Octo, the CHIP-8 development tool and emulator by John Earnest (MIT licence). The game is kept in the Chip8 Community Archive, which places everything in it in the public domain under CC0 1.0. The licence text is linked from this page.