ZX81 Computer


Showcasing monthly programs, a retro look at my my first computer., Page 4

Quickly Avoid the Spiders in the ZX81 Game Tarantula

Quickly Avoid the Spiders in the ZX81 Game Tarantula

Tarantula, August’s program of the month, was part of a pair of games that made me think I was a game developer. At the age of fourteen, I didn’t let problems like the lack of a distribution channel tarnish my dreams. Although I didn’t make it into gaming, it’s still fun to look back on what could have been.





Bringing an Old ZX81 Sketch to Life with BASIC Is Absolutely Crazy

Bringing an Old ZX81 Sketch to Life with BASIC Is Absolutely Crazy

Foreign to many developers today, I have a notepad and binder full of ideas from my ZX81 days. The notepad contains early program snippets. In contrast, I have sketches and designs crammed into a binder. Flipping through it, I landed on a Star Wars sketch that became the basis for this month’s program.




Can you hack the computer and save the world?

Can you hack the computer and save the world?

“Agent 51, your goal is within reach, but there is a problem.” “Understand,” you reply. Professional as always, you only allow a hint of annoyance in your voice. “Explain.” “Well, the plans are in the room in front of you, but the floor is a trap. You need to deactivate it using the terminal to your right.” You look down at the screen, a singular “READY” stares back at you. “Sounds easy enough,” you reply. “It isn’t. The interface is protected and, sadly, our operative died before he could tell us the code.” “So what do I do?” “You’re going to have to hack it. Our operative left a back door into the system, if you can find it. You can do it, Agent 51.” You nod at the voice in your ear. You can do this. Play begins with imagination. Computers are great for role playing and Code IV was one of my programs that helped enable a story. As a kid, I often augmented my play using my ZX81. Although the narrative above isn’t exact, it embodies what I was thinking when I wrote this month’s ZX81 program. Fun, adventurous, and unfair, can you crack the code and disable the floor?



Can you guess the right code to win?

Can you guess the right code to win?

I used to play Mastermind when I was a kid, a simple code breaking game. One player would set up a sequence of colored pegs and the other would have to guess it in a set number of turns. My version, called ZX Master Mind, has the computer creating the code. Can you guess the three numbers in sequence before your ten turns run out?


Can You Avoid Death in the ZX81 Game Stick Shift?

Can You Avoid Death in the ZX81 Game Stick Shift?

Dodging games were the rage back in the early ’80s. Wanting to add my own take on the genre, I created Stick Shift, November’s program of the month. The goal is simple. Dodge other cars, oil spills and spikes while not crashing into the wall. Mess up? Well, it’s game over for you. Don’t fret though, it isn't that hard—yet.


Bugers Will Kill You in October's ZX81 Program of the Month

Bugers Will Kill You in October's ZX81 Program of the Month

While working to improve the way I display my ZX81 programs, I ran across one that didn’t have a picture. Finding that odd, I did some research and found that I’d written a page for it back in 1999. To my surprise, I’d never uploaded it. To rectify that oversight, I made Bugers this month’s program.


Trail Blazer is my ZX81 Tribute to Tron’s Light Cycles

Trail Blazer is my ZX81 Tribute to Tron’s Light Cycles

One of the coolest movies when I was a young teenager was Disney’s Tron. What geeky kid didn’t want to watch a movie about computers and video games? Sprinkle in some computer animation and how could I not fall in love. Needless to say, Tron was the inspiration for more than a few of my programs. Trail Blazer, September’s program of the month, is one of them. An homage to the light cycle segment, the goal is to crash your opponent first. But beware. All walls are deadly, including your own.


Electon is August’s ZX81 Program

Electon is August’s ZX81 Program

I painted more borders on the ZX81 than just about any other shape. An easy way to confine movement, it shouldn’t come as a surprise that Electon starts by building a box. And before you ask, this month’s ZX81 program isn’t another version of snake. Instead, you use the Z, X, N, and M keys to move in an attempt to capture the Electon. Sounds easy? Better give it a try and see.


3D Image is July’s ZX81 Program

3D Image is July’s ZX81 Program

Not everything I wrote on the ZX81 was a game, although I did write a lot of those. In fact, some of my first computer programs did nothing more than print pictures. 3D Image, a badly named program, is one of my experiments in animation on the ZX81. Depicting a sun at the end of its life, it’s an uses simple math to generate an image.


Vargen Crown is June’s ZX81 Program

Vargen Crown is June’s ZX81 Program

“Jealous of Vargen’s accomplishments, a rival kingdom has attacked and kidnapped your king. As head Knight, you mount a quest to return the King, hidden somewhere in the forest by his captors. But hurry! The King's ransom has a time limit. Can you find the King in time and restore the Vargen Crown?” Sounds great right? An adventure game set in a single screen. I had high hopes for Vargen Crown. Castles, keys, and puzzles, our program of the month covered the basics of adventure. Using just the ZX81 cursor keys, playing it will leave you unsatisfied and, I suspect, quite frustrated. It’s too bad as the game has a decent look to it. I chalk it up to being a young programmer, but that's not an excuse. Still interested? Let’s dig in and see what makes this game tick.


Up Is Down in Faller, May’s ZX81 Program

Up Is Down in Faller, May’s ZX81 Program

Walls and creatures always make for a nice game and Faller, our program of the month, has both. It takes a bit of imagination, but watch the icky spider climb up the wall towards you. Their goal, of course, is to knock you off and claim the wall for themselves. Like any good hero, you sit at the top and move over the spiders using Z and .. But be quick and knock them off using M to save the day. Just don’t be a faller should you miss.


ZX81 Website Makeover and Twitter Experiments

ZX81 Website Makeover and Twitter Experiments

If you haven’t visited in a while, you may notice that my ZX81 retro computer site is looking a bit different. I’d been using newer, responsive themes, for almost a year now. Yet I was being selfish. The general population wasn't allowed to partake my fun. For the most part, this was due to me not feeling ready. The little bugs I saw prevented me from making progress. The coding perfectionist in me injected doubt which translated into no fun for the masses. No longer.


Laser Blast is April’s ZX81 Program of the Month

Laser Blast is April’s ZX81 Program of the Month

April is close to wrapping up and I was able to find time this weekend to type in another ZX81 game. Laser Blast, this month’s program, has you saving the world. Kind of cliché I know, but hey this was 1984. George Orwell’s novel didn’t come true, but at least we could blast alien’s with lasers. Use the Z and . keys to move and M to shoot your ray of death. But beware. The alien has a guided missile and it’s heading right for you.


Computact is March’s ZX81 Program

Computact is March’s ZX81 Program

Ah, spring time. As winter melts away, the weather goes haywire and it’s time to enjoy the bouts of sunshine, rain and the occasional thunderstorm of hail. Perhaps it’s fitting that in the middle of this meteorological mayhem that Computact came back to life. An outwardly simple landing game that is almost impossible to play. No matter, it demonstrates some interesting use of ZX81 BASIC as March’s Program of the month.


February’s Program: Telaport

February’s Program: Telaport

Digging through my listings, I struggled deciding what to offer for February. The first one I found was an adventure text game. Too close to last month's program, I decided against it for now. Further down in the stack, I found a code breaking program, but after entering it in I realized it needed work. The next program I pulled out, a graphic game called Teleport—ignore that spelling for now—ended up being just right.


January’s Program: Star Probe

January’s Program: Star Probe

Wow, 2016 and I’m still digging programs out of my stack of print outs. Kicking off the new year, I’m grabbing a story based program. I wrote Star Probe, our program of the month, in the style of a Chose Your Own Adventure book—and yes, I actually owned most of them. Although you can only enter numbers, Star Probe is actually an example of interactive fiction. Though not as advanced as an Infocom game, Star Probe delivers an interesting, if short, story to the player. Before I spoil where I drew my inspiration, go play it. It will only take a few minutes. Just try to ignore the horrible grammar and spelling of a 14-year-old.


December’s Program: Monkey Maze

December’s Program: Monkey Maze

Time to close out the year with another classic remaking. Back in 1983, I decided to try my hand at recreating Nintendo’s fan favorite: Donkey Kong. My version, cryptically called Monkey Maze, is December’s Program of the Month. Not quite as complex as the original, my version has only a single board that you can navigate around using the ZX81 cursor keys (5,6,7 and 8 which map to left, down, up and right). It plays pretty well. Go give it a try, and avoid the barrels, if you can.


November’s Program: Dragon’s Lair

November’s Program: Dragon’s Lair

One of my favorite video games as a kid was a rather unlikely one. It wasn’t the coolest graphics or excellent control. It was about story and animation. It was, of course, Dragon’s Lair. The odd laser disc game by famed animator Don Bluth. Not surprisingly, I tried to recreate a bit of the game's feel on my ZX81. My attempt is, of course, November’s Program of the Month.


October’s Program: The Haunting

October’s Program: The Haunting

It is Halloween and October’s Program of the Month is right on time. When I pulled the listing for The Haunting from my stack I knew it would be perfect. Although short, I knew I’d be challenged as this program of the month requires something I hadn’t needed before. That something was sound.