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CroZXy Road (2015)
My interpretation of Hipster Whale's iconic "Crossy Road".
Crossy Road is arguably the most iconic game of 2015 - instantly recognisable, simple to play, and ruthlessly addictive - and so it seemed only fitting to try and bring it back down to Earth, and back in time by 35 years, in the form of a de-make for the ZX81. The game has hit such a nerve with people - I've seen it played in pubs, on buses, even half way up a mountain side whilst holidaying in Italy - which I doubt will ever happen to my version (please send photographic proof if you try it!)

I initially contacted Hipster Whale early in 2015 about the prospect of a ZX81 conversion of Crossy Road, and I'll admit to being somewhat anxious as I waited for the reply, wondering quite what they'd make of this frankly crazy idea. At the time I'd thought very little beyond the idea that it could be cool, and a couple of mocked-up screens, but despite their hectic schedule they agreed to the project, and have been fully supportive of it since, and indeed named the game after liking my previous work on ZXagon.

Originally I planned the game to be 2D - looking very much like the original Frogger on which it is based, but after Hipster Whale took such an interest in the project I felt that simply wouldn't cut it, and so forced myself into the whole 3D concept, which although sometimes doesn't look so great in a still image (much like Ant Attack & One Little Ghost before it), works pretty well when everything is moving. As is usual with these projects, there were a number of false starts, and a major re-write towards the end of the development when the game quickly ran out of memory trying to get the level logic working.

I'm very proud of the end result, which I think is about as close as a ZX81 can get to the majesty of the original. Okay, so there's none of the collectable nature of the original, but I think that the claustrophobic nature of the original has been preserved. As a last note, it's probably worth mentioning that, despite all the time I spent playing the original game for research, I'm still really quite awful at it!

I've also been officially nerd-herded. :)

U-Bend (2015)
My interpretation of a Pipe-Mania game, with 36 unique levels.
Pipe-Mania, and the similar Locomotion, were games which often featured as type-in magazine listings for the ZX81, and the game itself has lasted the test of time, having had versions of it written for just about every machine there is.  The ZX81 has a few, I remember writing one (very badly I must add) in BASIC in 1982, so I thought I'd have another go at it.

The game itself is very straightforward - arrange tiles on a grid so water can flow from one to the next, building a pipeline to cover enough distance to complete the level - but the random and limited number of tiles, and the speed of the ever-flowing water, makes for an interesting and often frantic game.  Whilst researching this game using the ZX Spectrum version, I noticed it had Tetris-style bonus levels, which I never knew about (as I don't think I ever got as far as completing level 4), and so those are also in my version.  The 36 levels themselves are all based on those of the Spectrum version, but the passcodes for the levels are different (so no quick cheating!)

Following on from last year's Rebound, this game also supports the colour facilities of the Chroma 81 interface, and so the water is actually blue!

More details on the interface can be found here.

Rebound (2014)
My interpretation of a Breakout / Arkanoid game, with 32 unique levels, 16 ball directions, multiple balls, and power-ups.
Breakout has been a popular game now for over 30 years, and was probably one of the first games I typed into a ZX81 from a book of BASIC listings.  I realised recently that it was a game genre which I hadn't revisited since then, and also that there didn't seem to be proper modern version of the game for the '81 - so I thought I should give it a go, as every platform should have one.

Breakout - as Atari originally did it - is a reasonably straight-forward game to program, but the addition of bonus bricks, weapons, and multiple balls (etc) make it more difficult to code, but much more interesting and addictive to play than the original, which can frankly get somewhat boring after a while.  Again I've kept to the low-res display, which can make some of the 16 possible ball directions appear a little jerky in movement, but I don't think it detracts from the overall playability of the game.

This game is also the first I've written to utilise the colour facilities of the Chroma 81 interface, which provides a non-intrusive way of connecting any ZX81 to a modern TV (via a SCART cable), along with a ROM cartridge slot, reset switch, and also - and most importantly for this game - a method of adding colour to the machine, and in a way which is actually better than the Spectrum!

More details on the interface can be found here.

Pandemic (2014)
"That is not dead which can eternal lie... in a petri dish" (with apologies to HP Lovecraft)

The sequel 2010's VIRUS.
When Virus was released in 2010, I was proud of the game I had written - I still am - as a shoot'em-up that required a certain strategy to playing it, as you had a limited amount of bullets to tackle the outbreak with.  Pandemic is a sequel to Virus, but with unlimited ammunition you can now go in with all guns blazing without fear of running out of ammo at that pivotal moment (just the fear of being suffocated by the virus)

The game isn't just Virus with some tweaks and new levels though, the engine has been redeveloped to cater for more enemies, diagonal movement and firing, virus generators, and key walls to name but a few improvements.  The game is also three times larger than its predecessor, boasting 24 levels of biological warfare.

Just don't shoot the food!

ZXagon (2014)
My interpretation of Terry Cavanagh's masterpiece "Super Hexagon".
It's always good to set yourself a challenge (last year it was converting Ant Attack to the ZX81) and try to push outside of what you know to be possible.  Super Hexagon is a simple piece of software in concept, but the ZX81 is a simple piece of hardware in reality, and was never designed to handle fast full-screen geometry.  Originally, as a test to see what it might look like, I wrote the foundations of the game in BASIC - and it took about a minute to draw a single hexagon!  The final frame-rate is a pretty consistent 10fps, and that has taken a lot of work, and a slightly reduced screen size (it's drawing the middle 28 columns of the 32 column screen, so 2 either side are unused), but I think it works well.

Terry's various modern versions, and also the recent C64
conversion (Micro Hexagon), all display solid graphics, but there was no way the ZX81 was going to handle that, but I think that doing it in wireframe adds to the 'clean' look, fits with the white background, and also allowed for the shape changes to pentagons and squares of the original.   Another change is that this is now an endless spinner - as the ZX81 doesn't have persistent storage having an progress/achievement based system wouldn't work so well, and in this respect it matches the C64 demake.  I say endless, but it will end if you manage to play it for 1000 seconds - which is just over 16 minutes - and that would be a truly huge accomplishment!

Quack! (2014)
My interpretation of the mobile game 'Flappy Bird'.  Control a duck by tapping any key to make him fly up, and so avoid the oncoming pipes.
Everybody seems to be going crazy over Flappy Bird at the moment, and a lot of clones have instantly appeared on the market - so why not one for the ZX81?

Written in an afternoon to capitalise on the media frenzy, it's got all the gameplay of the original, but none of the in-app adverts which have been making the author so much money recently - but you can always use the Donate button on the home and download pages to make me rich! ;D

Ant Attack (2013)
My interpretation of Sandy White's classic isometric title from 1983.

"The Walled City of Antescher has rested for a thousand, thousand years in the midst of the Great Desert inhabited by only the deadly Ants who have made it their home. The sands have piled up at the walls but for some reason have never encroached upon the city proper. The City rests dreaming of past glories, solid and unmoving; the signature of a long dead race. The City washed clean by the sun's rays. The city lost from the world of men for days without number..."
Writing One Little Ghost proved that the ZX81 was indeed capable of doing justice to an isometric game, and so I started to think about pushing further to a game which had layers of blocks - a proper 3D isometric game.  Ant Attack quickly became an obvious choice for that game, but if I was to do it justice I had to somehow get a 48K Spectrum game into the humble 16K of the ZX81, and I already knew that the map data alone consumed 16K of the original.  Initially I wrote a map viewer to show a compressed version of the map on the ZX81 as a proof-of-concept, and posted a picture of it into the guest book on Sandy White's website, along with an brief explanation of what I was planing to do, and asked if he was OK with the idea...

Luckily he was, and more than that we started to work together on the idea of using some of the code from the original in order that this not just be a remake but as close to the original as possible.  Over six months later, and numerous redesigns of my code as I repeatedly ran out of memory, and the game is finished.  I'm really pleased with the result, not just from a coding stance but also in my appreciation of the original game, how it was coded, and just what an amazing game it still is.

For more information on the original game, visit the Ant Attack page on Sandy White's website.

Sandy White - "Awesome!  You've really pulled off a Miracle!  I'm grinning ear to ear!"
Philip Oliver - "Taking it to the ZX81 - you're going the wrong way!"

One Little Ghost (2012)
My interpretation of Namco's 1980 arcade game 'Pac-Man'.

If you ever felt sorry for the ghosts, the orphans they left behind, and wondered what would happen when Pac-Man became the ruling elite, then this is for you.

Whilst researching to see if the ZX81 was capable of doing justice to an isometric game along the lines of Ant Attack! or KnightLore I coded a program to display a single height map of tiles, and it looked a bit like a maze.  Along with the code examples, I'd also been experimenting with the graphics required for such a game, and produced a cute little ghost.  An idea then began to germinate... a maze, and some ghosts?  Why not try a scrolling isometric Pac-Man?

I'm still not sure if a full isometric game is possible (that's for another day) but a scrolling flat one certainly is, and I'm really pleased with the results.  It looks good, is fluid and responsive, and features most of the aspects of the original - including the (slightly bugged) A.I. and attack patterns.  Having a ghost as the main character means that I've had to supplemented the concept of 'lives' for 'spirit' - I mean, a ghost doesn't have a life, does it? - which introduces a slight twist on how you play the game.

MicroMart - "Bob Smith has done it again with another superb release for the ZX81.  This is a pacey, technically impressive, playable and addictive high-quality release.  This is, for now at least, the best game for the monochrome 8-bit that I've ever played.  I'm sure even Sir Clive Sinclair would like this one"

Oldschool Gaming - "It seems pointless in making any grand claims to how good One Little Ghost is: and saying that it's simply superb does not in anyway diminish Bob's other games, nor does it trash those classic games such as J. K. Greye Software's 3D Monstermaze, Don Priestly's excellent Mazogs or Rocket-Man published by Software Farmhouse, to name but three. Simply play it for yourself: take away the hardware and you still have a damn good, fast, playable and most importantly fun game." - 9/10

SirMorris (RWAP ZX81 forums) - "This game rocks more than a cross-channel ferry with a broken stabilizer"

Impact! (2012)
My interpretation of Atari's 1979 arcade game 'Asteroids'.
One of the reasons I turned my attention to the ZX81 was the lack of good games for it, and by that I mean graphically rich, fluid, and responsive games.  One of the games which I felt was furthest from being this on the Zeddy was Asteroids, as the versions of it released at the time were largely slow, unresponsive, and difficult to play (I mean, having your ship displayed by the digits 1 to 8 depending on which direction it was facing? Really?!)

So, I decided to write Impact! as my interpretation of the game - featuring smooth movement, fluid gameplay, player inertia (always loved rotating, thrusting, and firing all at the same time), and graphics which actually look something like the original arcade.  It is missing the enemy saucers which appeared in the arcade version, but given the smaller playing field (the 64 * 46 effective pixels) I don't think that is a huge loss as the game is frantic enough without them.

RetroGamer - "The enemy UFOs that occasionally drift across the play area have been left out of Impact! [but] that ommision doesn't prove to be a major one in the long run and the game is still fun" - 86%

Noir Shapes (2012)
Move the various shapes into a given space to complete each level, ensuring that none of the tiles overlap at any time.  It may sound simple, but with limited room in which to arrange the tiles within things soon start to get claustrophobic...
Following from the excellent Miner Man another conversion of one of Electric Wolf's Xbox 360 games to the ZX81.  Again, it doesn't have some of the in-game features, any sound, colour graphics, and such like, but this time we have managed to improve upon the original by adding an extra 12 levels to take the total to 60, and have even converted the use of an avatar from the original!

More details on the original game, called 'Cool Shapes' can be found at the Electric Wolf website - - which also contains a link to the Xbox marketplace where you can shortly download the demo or full version of the game.  There is a video of the game on YouTube -

Miner Man (2011)
"Play through 60 levels of puzzles, mazes and traps. Each level will present the player with different amount of gems to collect. To collect the gems the player will have to work through the levels avoiding the traps and solving the puzzles." (taken from the original game)
Possibly for the first time in history, a ZX81 conversion of an Xbox 360 game - two machines separated by 25 years.  Admittedly it doesn't have all 60 of the original levels, some of the in-game features, any sound, colour graphics, and all the rest, but it does take over 1100 times less memory to run!

More details on the original game can be found at the Electric Wolf website - - which also contains a link to the Xbox marketplace where you can download the demo or full version of the game.

Although the game may look similar to Boulder Logic released earlier in the year, and indeed that supplied the starting code-base, the game logic is very different - the boulders don't fall under gravity, but instead roll in a preset compass direction - changing the game from an against-the-clock arcade game into a crafty puzzler.

Boulder Logic (2011)
Bradford Walker-Smythe needs to find the perfect engagement ring to win the heart of his true love Tania when he asks for her hand in marriage.  And so, to prove his devotion, he sets off to the Cornish mines in search of the perfect diamond...
Another kind of game I haven't written before.  All of the examples I'd previous seen for the Zeddy didn't look very impressive - all single-screen with single-character graphics - and so I felt now was a good time to try and write a better looking and more playable version, with larger graphics and a fully-scrolling playing field.  I'm also quite proud of having managed to fit 32 levels into the final game, which could possibly be a record on a 16K machine.

OldSchool Gaming - "...this is a great implementation of First Star's classic Atari 400/800 game Boulder Dash, and with 32 levels is probably the biggest game ever on the monochrome Sinclair...  In my opinion, this is the best ZX81 game ever, just beating Bob Smith's Virus by the finest of margins. Taking the limitations of the hardware out of the equation, Boulder Logic is still a very, very good game" - 9/10.

RetroGamer - Sizzler - "Boulder Logic is Bob Smith's attempt at cramming the challenge of Atari 8-bit classic Boulder Dash into 16K of ZX81, and it is admirable...  The difficulty has been pitched well too, challenging players from the start and letting them discover the means to get through each stage..." - 90%

Virus (2010)
Never did like office parties...

Christmas eve, and the staff at Macrobiology Industries Limited were having the usual office party, with all the usual hi-jinx and tears, but something very unusual was happening in the biohazard containment fridge.  The predicted pandemic had never occurred, and so the fridge was full of unused swine-flu vaccines, but that night it jostled for space with the secretary's cucumber sandwiches and the boss's - sorry, not his, a friends - Viagra supply, all stored there for safe keeping until the party really got started.  But the disco lights overloaded the generator, the fuses blew, the fridge shut off, and the staff all went their separate ways home to sleep off the excesses.

January 2nd, happy new year! The security guard, first on site that morning, was slowly working his way around the offices and labs, tripping the fuse boxes back to life.  He shook his head, bemused by the broken hinges on the doors, but the smashed containment fridge, and mucus-like stains on the walls and floor scared him enough to grab his SHARPS pistol, as strange things moved just out of sight...

I started my second game for the Zeddy, following the good reception received by Domin8tr1s, with high aspirations.  Having a character-mapped display I felt the machine should be capable of a fast scrolling game, and it was.

MicroMart - "Virus is a very playable and extremely polished top-down shoot'em up, making the most of the machine's limitations.  Put simply this is Speccy-quality gaming on a ZX81" - 9/10

RetroGamer - "The phrase 'tense scrolling action on the ZX81' isn't one we often use in these reviews, but that's exactly what Virus is." - 85%

Domin8tr1s (2010)
Arrange the dominoes as they tumble from the sky so that matching digits are adjacent, either horizontally or vertically, to each other.  Align the same number of digits as the digit itself to make those dominoes disappear.
Originally written for the ZX Spectrum in 2005 as a test to see if I still could, and still wanted to, code in Z80 assembler, it seemed a perfect choice to attempt this game again as my first title on the ZX81.

Thanks to contributions on the "Bob's Stuff" Facebook page, and also of the ZX81 forums hosted by RWAP services, the game has grown and improved from its original implementation with new features, such as Bombs, a larger playing area, an additional control method, and the option for initial random rows.

MicroMart - "This game is an interesting and thoroughly enjoyable one... At least as good as its Speccy counter-part, and has more options to you with in relation to how difficult you want the game to be." - 7/10