a game by Peter J Hopkins

Isostasy. Equilibrium. The balance between opposing forces. Hot and cold. Solid and liquid. Light and dark. Peth-Luk and Gol-Luk, the gods that emerged from the Isostasy at the initiation of the current Fathom...but those are only myths...

Click here to download the Isostasy Demo! This is a .nes rom file, playable on any NES emulator or flash cartridge.

Click here to get the free demo or buy the full game on Itch! This link goes to the page for this game. (To run the PC version of either the demo or full game, extract the contents of the zip file to your preferred directory, then run Isostasy.exe)

Click here to get the free demo or buy the full game on Steam! This link goes to the Steam page for this game. (if you download the game or demo from Steam and want the NES rom file to play on an emulator or flash cart, navigate to the directory in which the game was installed and locate Isostasy.nes or IsostasyDemo.nes, then copy and paste it into the location of your choice.)

Beihnn's Journal


The land is changing. Day by day, the fruit that I gather seems to be smaller, more bitter. It is getting harder and harder to glean a living from the forest. And I never used to have concern for my safety out and about, but the once gentle forest creatures have turned vicious, driven mad by some unseen force. It is as if the soil itself is slowly being poisoned. All my heart desires is to live peacefully here in my cabin, but I do not know how much longer that will be possible. I plan to go visit the old sage who lives deep in the forest and ask for guidance...


Getting Started

Title Screen: Use the Select button to choose between starting a new game, or entering a password to continue a previous game.

(If playing on a PAL region console, you can hold Select and press Right to switch game to PAL mode. Holding Select and pressing Left will switch back to NTSC mode.)

The Playfield

1: Energy Meter. When you run out of energy, you are knocked out and go back to your most recent checkpoint.

2: Door. Use doors to access different areas. Press Up to go through them.

3: Beihnn. You control Beihnn as you play the game.

4: Enemies. Touching enemies will drain Beihnn's energy. Shoot enemies to reduce their energy and knock them out.


(When playing the PC version, either the keyboard or a gamepad can be used. Default key mappings are shown here. Default gamepad button mappings may vary.)

Left and Right: Movement. (Left and Right arrow keys on keyboard)

Down: Duck. Hold down while pressing left or right to crawl through narrow passages. (Down key on keyboard)

Up: Enter doors, use teleporters, talk to people, examine things. (Up key on keyboard)

Select: Enable and disable TNT. ("D" on keyboard)

Start: Pause game. View status screen. ("Enter" on keyboard)

B button: Fire weapon. Set TNT if enabled. ("A" on keyboard)

A button: Jump. ("S" on keyboard)

The A and B buttons on controller 2 can be used to select different weapons at any time during gameplay. ("W" and "Q" on keyboard)

PC version only: the Pause/Break key can be pressed to reset the game to the title screen at any time, similar to the Reset button on the NES console.

Note: These instructions are written with the NES controller in mind. If you are using a keyboard for input, remember that the "A" and "B" buttons are mapped to the "S" and "A" keys respectively.

Status Screen

(PC version only) Press Select (the "D" key) while on the status screen to access the settings screen (see next section).

Fruit: The total amount of fruit you have collected. The more fruit you have, the luckier you become!

Time: The length of the current game. Displayed in Hours-Minutes-Seconds-Frames.

Inventory: The total number of each item collected.

Weapon Select: With the cursor on the current weapon, press left or right to select a different weapon.

View Password: Press down to select this option, and press 'A' to view the current password. Press any button to return to the status screen. (PC version only: viewing the password will also save your game data file in your Documents directory automatically. This will overwrite any existing save file, so if you would like to preserve multiple save files, copy them into a separate directory of your choice.)

Map: Press down again to reach the map. Use the D pad to navigate around the map. The map will display the areas that you have visited since the last reset. If you have the Atlas for the current zone, then the entire map will be displayed. There are two markers you can place on the map using the 'A' and 'B' buttons. Use these markers to remind yourself of places you want to explore later on.

Below the map are arrow icons. Select these to view the maps for other areas you have visited.

*Note: Passwords do NOT preserve the areas of the map you have visited! System reset erases this data! To preserve the map for a zone, you must collect the Atlas for that zone. The locations of the 'A' and 'B' markers that you set ARE preserved, so use them to help you remember where to go.

if you are stuck, while the game is paused, press Up and A on controller 2 to return to your last checkpoint. If you are completely stuck, you can return to Beihnn's cabin. While the game is paused, press 'A', 'B', Select, and Start at the same time on controller 2. This will cost you all of your fruit, TNT ammo, and the last item you collected.

Settings Screen (PC version only)

Press select ("D" key on keyboard) while the game is paused to access the Settings. Press start or select to return to the game.

Use the Up and Down buttons to select a setting and the A or B mapped button to change it.

Size: Reset the Window to a fixed size, from 1x to 4x.

Aspect Ratio: 4-3 simulates the pixel ratio on a CRT television. 8-7 uses square pixels.

Sprite Limit: 8-sprite-per-scanline limit like the original NES PPU. Setting to 'off' reduces sprite flicker.

Overclock: Emulate more cycles per second than the original NES CPU. Setting to 'on' reduces lag.

Audio Volume: Changes loudness of game audio, from 0 (mute) to 10 (full volume).

Controller Button Mapping: You may customize the button or key mappings for each controller. When a controller is selected, the button cursor will appear. Press the key on the keyboard or the button on the gamepad that you want to map to the selected button on the original NES controller. the cursor will automatically move to the next button. All buttons will be mapped in sequence for that controller until finished. Only one gamepad is supported, but the buttons for both controllers can be mapped to that single gamepad (note the default button configuration: the A & B buttons on controller 2 are mapped to the L & R shoulder buttons to allow quick weapon changes during gameplay).

*Note: At any time during gameplay, the Esc key can be pressed to exit the game, Pause/Break can be pressed to reset the game, and the Home key can be pressed to restore the default button mappings. As such, these three keys cannot be mapped to any controller buttons.

Password Entry Screen

D Pad: Select a character.

A button: Enter a character.

B button: Backspace.

Start: Enter the password. If it is correct, the game will resume at the appropriate checkpoint.

Select: Return to the Title Screen.

(PC version only) If a valid Isostasy save file is found in your Documents directory, the password will be auto-populated, along with your map data and custom settings. Just press Start (Enter) to resume your game.

The Environment

Checkpoints: Doors with a spherical symbol over them are checkpoints. If you are knocked out, you will return to the last checkpoint you went through. When the game is paused, you can press Up and 'A' on controller 2 to return to your last checkpoint as well.

Damage Tiles: Throughout the game, you will encounter tiles that cause damage when you touch them. Try to avoid them if possible, but you may have to pass through damage tiles to explore some areas.

Moving Platforms: Use these to explore areas you would not otherwise be able to reach. Different colored platforms have different properties. Hint: Platforms with [!] above them periodically disappear, so watch your step!

Gravity Tiles: Touching these tiles will fling you rapidly in the direction the arrow points. Press 'A' for a boost!

Water: Reduces speed and jump height. Note: experiment with gravity tiles under water!

Crumble Blocks: These can be broken when you shoot them.

Ice: Slows acceleration and turning, but increases max speed. Jump to regain your footing.

Teleporters: These will transport you to someplace far away...

Sages: Press Up to talk to sages. They will give you information.


Power-ups are dropped by enemies that are defeated. Some are more rare than others.

Fruit: Everybody loves fruit! the more you collect, the luckier you become. Each zone has its own type of fruit.

Pea: Restores a small amount of energy.

TNT: Refills two units of TNT ammo.

Potion: Grants a short period of invincibility.

Snowflake: Freezes all enemies for a brief period of time.

Crystal: Restores all energy and TNT ammo.

Atom: Vaporizes all enemies on the screen at once.

The Different Zones

Forest: The location of Beihnn's cabin and the beginning of the game. A good place to get a feel for the game's controls.

Cave: Deep inside the mountain, tunnels have been carved out by an ancient civilization. Make sure to explore every corner!

Tundra: The frozen woods on the other side of the mountain. Your reflexes will be tested here!

Plains: Open lands and big skies await. You may need to backtrack and find more items if you aren't strong enough for the enemies here.

Beach: Fun in the sun! Don't be afraid to explore under water. You might find a path forward that way...

Marine: This entire zone is under water. Legends tell of ancient technology sunk beneath the waves.

Space: You must teleport into the Space zone. It's out of this world! Take your time and adjust to the weird physics.

Fortress: Millennia ago, terrible things happened here. Could it be the origin of the force that poisons the land?


Items are hidden throughout the game.

TNT Barrel: When you acquire TNT, press select to enable it, and then 'B' to set it. Each barrel increases the total amount you can carry.

Pumpkin: Increases your total amount of energy.

Atlas: Each zone contains an atlas, which will display the entire map for that zone on the status screen.

Peppercorn: Increases the strength of your weapons.

Gum Shoes: Allow you to jump higher.

Lily Pads: Negate the effects of water on your movement.

Force Field: Reduces harm from enemies and damage tiles.

Mill: The weapon you begin with initially.

Mortar: Fires shots that are larger and stronger.

Grinder: Hold 'B' to Turn the crank and spray shots all over the place.

Scoop: Flings little balls that bounce around.

Laser: Penetrates enemies and keeps going.

Quantum Fluxitator: Fires shots that can go through walls.

Brulee: Hold 'B' down for a continuous flame.


Cool Blob: Slowly oozes around, looking for nutrients to absorb. With sunglasses, very cool indeed.

Bazz-Up: Builds hives in old trees and rocks. Fast, but not too strong.

Ache Corn: Look out! It will fall if you get too close.

Bug-a-Back: Crawls around in circles, acting purely on instinct.

Spoder: It can't weave webs, so it simply drops onto prey from above. Creepy.

Bouncer: Temple guardian. But what could be worth guarding?...

Cock-a-Rock: Wanders back and forth, spitting rocks at whatever it sees.

Slub: Enjoys narrow passages. Always seems to be in the way.

Fire Frog: Attaches itself to the ceiling and spits fire rings at intruders.

Ignes Fatui: Are these the spirits of those who have wandered too far and became lost?...Nah...

Dumbat: Large numbers of these inhabit dark, dank places.

FuzzBall: Aww, I just want to hug it (bad idea).

Birb: Swoops down from the sky to attack.

Flobby: A bad kitty. (Sometimes if you are very lucky you may find a good flobby!)

Armor Blob: A big blob with armor plating on the front. Shoot it from behind.

0-4 Tuna: Velut luna, statu variabilis!

Fleet Fish: This fish is in a very big hurry to get somewhere.

Squib Cakes: Bobs along mindlessly, but it has a strong sting.

Start Fish: Hides in holes. If you startle it, it will jump out at you.

Winged Worm: Flies around being a pest.

Evil Eye: Oh god, it's moving right towards you!

Chewie: A disembodied mouth, searching desperately for something to chew on.

Sk8rboi: Ice skates everywhere it goes. I wonder what it looks like under the hat...

Brains!: Guards the fortress against curious intruders (like you).

Odd Eye: Squish squish!

Mean Blob: Attempts to smash anybody that walks below it.

Psycho Blob: Always appear in groups of three that are psychically connected. You must find a way to shoot all three of them at once to destroy them! Hint: If you only see one or two and you need to shoot all three to progress, walk away and then come back...maybe they're a little shy...


Sass Squash: Lives in the Forest Zone. Does NOT appreciate visitors! (very sassy.)

Shellack: A giant turtle-like creature that roams the caves. Shoots rocks from a hole in its shell. Most weapons bounce right off!

Winter Squash: Sass Squash's cousin in the tundra, with breath so cold it can freeze you in place.

Deth Chickum: This crazed bird attacks without mercy, and has an inexhaustible supply of worm-filled eggs.

Camilla Piranha: Look for the bubbles to see where Camilla will jump next. *Hint: The sound will tell you what to expect.

Akwa-Tock: An ancient, heavily armored mechanical weapon, abandoned deep under water. *Hint: A frontal assault is useless. Find its weak point.

Alium: A creature from another galaxy. It doesn't seem to want you to go any further.

Wizard: Ammbraxz's assistant. Reflects away all weapon fire. There must be a way...

Ammbraxz: This name is only whispered in hushed tones. Who is Ammbraxz? Evil sorcerer? Mad scientist? Ruthless megalomaniac? You must find out. It will be your final test of strength and intelligence!

At the conclusion of your adventure, you will have the opportunity to select a new Beihnn and begin again. Some things may be different the second time around though...

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