Here you can find some ZX Spectrum games I have developed for different purposes (besides having fun!):
 THE LOST ONE |
 LA ISLA DE RUTH (LA SED) | ||
 B1TFACTORY |
I have written other software related to the ZX Spectrum, such as the Nutria emulator and the ZX Ecosystem library for writing ZX-like programs for modern computers in C++.
This game is coded in pure Sinclair BASIC for the "Concurso BASIC Bytemaniacos 2025" contest. It has been devised as an evaluation of procedural tapes, a scripting language for better and more efficient development of pure BASIC programs; they allow for automatic optimizations, like the ones of the ZXBasicus tool, on the fly, while loading the .tab.
The Lost One is a puzzle/platform game where your PATIENCE, INGENUITY and DETERMINATION are crucial, since you do not control the main character motion: it moves constantly (with a strong trend towards going to the right) and picks up automatically any tool object it finds in its way, up to a maximum of 9 for each kind of tool. There are 7 kinds: vertical dig, right excavation, left excavation, pave to the right, pave to the left, column build and parachute.
The game is a tribute to the classical "Lemmings", adapted to the limitations of the ZX 48K. In this adaptation, your tribesmen departed a long time ago to the Twenty Cursed Caves in their quest for the Sacred Cliff, where all the evil ends and a new generation can thrive. But you were the dumbest, slowest of all, and your body does not always obey your mind. So they left you behind. Only a few pitied you and laid down their tools along the path after use, instead of keeping them for the Cliff. Will you be able to use them wisely, in the correct moments and sequence, to make your way through the Caves and reach your mates at the end?
The game is shipped with a Cave Creator, the same used to design all the original caves. Further instructions for both the game and the Creator are included in the .zip file.
The game achieved a 7th place (out of 30 participants) in the "Concurso BASIC Bytemaniacos 2023" contest, where many other high quality programs participated. In the webpage of the contest you can download all of them and test them in your ZX or an emulator!
It has been reviewed in the BreakSpace e-zine Issue 3 and more briefly in the recently resurrected Microhobby magazine. It has also been included in the Spectrum Computing archive with a score of 7 (as for Dec 2025); a map of the original caves is available there.
You can download here the version that was submitted to the contest as a .ZIP file.
Also, David Hughes (Breakspace e-zine) has designed a very interesting (and difficult!) cave that you can download and run directly in this .SNA file.
This is a text adventure written in Spanish for the "Aventura Bytemaniacos 2023" contest. It is coded on a modified MuCho engine for the ZX Spectrum 48K.
The game is a tribute to a boardgame of the 80s that was marketed in Spain with the name "La isla del diablo" in a collection of small, cheap games called "FeberJuegos". In that game, a bunch of adventurers had to survive to a shipwreck on an island full of monsters and demon spirits. The game experience was strongly dependent on randomness through die rolls.
"La isla de Ruth" is also set in a mysterious island, but now the player takes the role of one of the shipwrecked sailors and a whole, scientific horror story is unveiled progressively as she tries to reach the boat that can save them. With two possible endings and more than one path that lead directly to death, the game exploits the limited memory of the ZX as much as possible.
This adventure is a choice-based game (no typing by the user) with specially dense and detailed descriptions devised to provide an inmersive experience, as close as possible to reading a short horror story.
The game was awarded with the 2nd place in the "Aventura Bytemaniacos 2023" contest, where other high quality programs participated. In the webpage of the contest you can download all of them and test them in your ZX or an emulator!
In April 2025 the game has been edited physically in a classical cassette tape, sold by Matranet. All the benefits from its sale will go to future calls of Bytemaniacos contests.
You can download here the version that was submitted to the contest as a .TAP file.
This is an educational game written in pure 48K BASIC that is intended for learning and practicing the bit manipulation operations present in common programming languages.
The game is set in an industrial factory. The goal of the worker (you) is to manufacture as many products as possible in the shortest time. For doing that, you are the operator of machines that can transform the raw materials according to certain rules. But, watch out! If you operate incorrectly, the factory may be jammed!
The game is played with the keyboard:
This game has been optimized and synthesized with ZX-Basicus, tested with the ZX-Basicus interpreter (zxbasicus -r --delay 10 -i ./bitfactory.bas) and with the Fuse emulator for Linux; the UDGs have been designed with BasinC; the background image has been adapted from a free Pixabay picture, using Retro-X.
The game was developed for the Bytemaniacos 2020 ZX Spectrum BASIC coding contest.
You can download the version the was submitted to the contest as a .TAP file.
These games have been developed by me (Juan-Antonio Fernández-Madrigal).
If you are interested in this work, you can use "software" (remove quotes) at jafma.net.