Tape Version RZX Demo
Manuals Cover


The whole world warned you that this damned formula you invented was going to be dangerous, but you did not pay any attention. You were believed to be very smart but now you begin to put your hands to your head. The reaction is already running and atoms will not stop escaping. Group them and get rid of them if you do not want bring the Universe to a standstill.

Isotopia is an adaptation for Spectrum of the Atomino game created by the mythical company Psygnosis for Amiga, Atari and PC computers. The development of the game faithfully preserves the mechanics of the original game, although all levels are newly created for this version.


You must place the atoms that are falling down into the test tube onto the board whilst trying to group them together to form a molecule. The game ends if the test tube fills with atoms completely.

Every atom has between 1 and 4 electrons that specifies the number of bonds it can make with adjacent atoms. (Blue atoms have 1 electron, red 2, green 3 and yellow 4.)

On having placed an atom on the board, it will automatically create as many bonds as is possible with adjacent atoms having free electrons. (But only a single bond can exist between each specific atom pair.

The atom always tries to establish the bonds in a certain order. The pointers (within the cursor) indicate at all times which bonds would be formed on placing the next atom.

The cyan "wildcard" atom appears in the test tube without electrons. When a wildcard atom is placed on the board, it will establish the maximum possible number of bonds without leaving any free electrons available on itself. It always fits perfectly. However, if on having been placed, it cannot establish bonds with any atom, then it will simply disappear.

To complete a molecule, none of the atoms that compose it can have any free electrons remaining. Once completed, the molecule will disappear from the screen. On starting each stage, the target to complete is indicated as follows:

  • Make X molecules (Haz X moléculas): You must complete the specified number of molecules. Any created molecule will be counted, independent of the number of atoms that compose it. (In practice the minimum number of atoms is 2.)
  • Make X molecules with at least Y atoms (Haz X moléculas con al menos Y átomos): Any molecule formed with less than Y atoms will be erased from the screen, but won't count as valid. After the quota has been fulfilled, you must clear the screen of atoms.
  • Eliminate the atoms (Elimina los átomos): You must leave the screen cleared of atoms. At the beginning you will find a number of fixed atoms already placed in the board.
  • Complete the pattern (Completa el patrón): You must make a molecule that occupies all of the available space. If you don't fill all the space, the molecule will disappear, but it won't be valid.

There are a total of 100 stages to overcome to complete the game.

IMPORTANT: No stage will be completed whilst even only a single atom remains on the board!

  • Think carefully before placing a new atom. Try to organize it the best possible way according to the already placed atoms, saving space.
  • Do not neglect atoms regardless of their location within the game area. Remember that the stage is not completed until there are no atoms remaining on the screen. That is the objective.

Compatible with all Spectrum models with 128k. Independent versions for Spectrum +128/+2 and Spectrum + 2a/+3.

Restart computer, select LOADER option and press PLAY on cassette.


You can move cursor freely through the play area laterally and horizontally.

To change a single atom on the board you have to move the cursor onto it and press SPACE/FIRE. The atom on the board will be swapped with the first atom in the test tube.
  • Keyboard: Default keys are:
Q - Up
A - Down
O - Left
P - Right
SPACE - Put/Change atom
  • Joystick: Sinclair Joystick compatible. Connect joystick on Port 1.

The scoreboard of the game provides to you the following information:
  • Number of current stage (NIVEL).
  • Number of molecules to complete (FALTAN).
  • The minimum number of atoms that must be in a molecule for it to count (MINIMO).
  • Number of atoms that compose the molecule currently under the cursor (ATOMOS).

Whenever 10 stages of the game are completed, there's a code provided thatr can be used in the initial menu to begin directly from the last completed level.


Insert code 0 0 0 0 0 then press key 7 and you will see the end of the game.


  • Programmed in BASIC and compiled with HiSoft BASIC 3.
  • 100 levels with different challenges.
  • 209 UDGs and 5 different graphic screens.
  • 5 tunes of 128K music.
  • A total of almost 90k of code and data simultaneouly in memory.


  • Code: Jorge del Llano (Forsaken)
  • Graphics: David Mochales (Workbench)
  • Music: Sergio Vaquer (Beyker)
  • Cover: David Clemares
  • Testing: Javier Ortíz

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