Numbertron for the Sharp MZ-80A & Sharp MZ-700

Numbertron is a single- or multiplayer puzzle game for the Sharp MZ-80A and Sharp MZ-700.

Numbertron is a pretty simple game, but you need to consider your moves carefully if you want to set high scores. The game is also surprisingly fun in multiplayer!

The game is now on!

There are a lot of changes for the 2021 version. Especially for the MZ-700 version, which has received a lot of improvements and general polish. The game is still free to download, though there is now an option to name your own price if you wish.

How to play

Numbertron on the Sharp MZ-80A.

The goal of the game is to aquire points by clearing the screen of numbers. However, in the process you will leave behind blank spaces, which will kill you should you move onto them later on in the game. You will need to plan ahead to avoid trapping yourself, or cutting off portions of the screen from further movement.

One or two players may play. In two player mode, you may also try to kill the opponent by trapping him or her. Or you may cooperate to clear as much of the screen as possible – your choice. The player who survives the longest will get a score bonus at the end of the game.

Your position is shown by the flashing cursor. You may move in all the eight directions, using the keyboard. To make a move, you need to first press the button for the desired direction. The cursor’s position will now change. Take note of the number under the flashing cursor – it will dictate how many spaces you will move. If you wish to proceed with the move, press the same direction key again. If you press any other key, you will abort the move.

Clear the screen.

Note that you may not move directly onto a space that does not contain a number. In other words, you have to already be moving in order to pick up bonuses, you may not stand next to one and grab it directly.

If there are no valid movement options, the game will be over.

Once a move has been confirmed, it may not be aborted. If you hit a blank space or one of the arena’s walls during the movement, the game will be over.

Default movement keys

Player 1:


Player 2 (MZ-80A version):

7 8 9
4 6
1 2 3

Player 2 (MZ-700 version)

K ;
, . /


The default MZ-80A-version movement set for player two is intended for the numeric keyboard, if you’re playing on a system without it, you should select the redefine keys option in the main menu.

Scoring and bonuses

The new MZ-700 version.
The new MZ-700 version.

Score is added for each move, even if it is not successful (however, it needs to be successful for the diamond to trigger). It is calculated like this: If you move 1 space, you get 1*1 points. If you move 2 spaces, you get 2*2 points – and so it goes all the way up to 9*9. High risk moves pays off! All bonuses may be individually disabled or enabled in the main menu.

Heart: Triples the score for the current move. If you hit another heart in the same move, it will triple again (theoretically, this may happen any number of times, but the likelyhood of it happening more than twice is quite small).

Diamond: This will double your current score. In other words, it is a good idea to save the diamond for when you’ve racked up a decent score already – but don’t wait until it’s no longer reachable! Note that in two player mode, BOTH players will receive a doubling of the score when the diamond is picked up. So make sure you have more points than your opponent if you’re going for it!

Clover: This will refill a random number of empty spaces with new numbers for you to plough trough. You will get points for every space that gets refilled. Clovers can be set to respawn, providing infinite play, though you will only get points the first time you activate it.

Main menu

Use any key in the top row of the keyboard to move up, any key in the bottom row to move down. Space to select/toggle options.

Main menu.

Menu options from top to bottom:

Start 1 Player game – Starts a one player game with the selected options.

Start 2 Player game – Starts a two player game with the selected options.

Enter names – Lets you type in names for one or two players. Hitting the enter key without typing anything in will result in the default name being used (or the last name typed in for that player).

Hearts – Space to toggle between on and off. If on, this will place a random number of hearts on the playfield.

Diamond – Space to toggle between on and off. If on, this will place a diamond on the playfield.

Blanks – Space to toggle between on and off. If on, this will place a random number of blank squares on the playfield.

Redefine keys.
Redefine keys.

Clover – Space to toggle between on, unlimited and off. If on, this will place a clover on the playfield.

Max number – Space to cycle through the values 5 to 9. This decides the highest number that will be generated on the playfield. A max number of 5 would result in a much easier game.

Slow moves – Space to toggle between on and off. If you turn this off, moves will be just about instantaneous. If you’re an experienced player, this will speed up the game a lot.

Redefine controls – Lets you change the movement keys for each player. Also provides a helpful reminder of what the current keys are, if you’ve forgotten. Note that the default controls for player 2 are meant for a system with a numeric keypad, such as the MZ-80A.

When toggling various features and bonuses, note that the game will dynamically change the game mode from «full game» via «custom game» to «simple game». «Full game» is chosen when all features are enabled and the max number is 9, «simple game» is chosen when all features are disabled and the max number is 9, and «custom game» is chosen in any other configuration. These are scored separately.

This is a video of the game being played on a real MZ-80A (thanks to Sharpworks for the video):

This is the current beta on the MZ-700 (thanks to Sharpworks for the video):

How to run the game

Included in the archive is the game on an .mzf-file. This is basically a tape image, and can be converted to a sound file (.wav) using MZFStudio, and recorded onto an actual cassette to run on real hardware. It’s pretty easy, though you obviously need a cassette player connected to your PC.

If you decide to play on emulators instead, EmuZ-80A by Toshiya Takeda and Hideki Suga is by far the best option that I know of. MZ-700-users should use EmuZ-700. After setting up the emulator, you simply load the game by attaching the .mzf-file (if it doesn’t load automatically, type L and press Return in Monitor).

Compatibility notes: Numbertron was designed for the Sharp MZ-80A. I do not know if it will run on the MZ-80K. It works on the MZ-700, but be aware that the sound effects play faster there, and there may be visual effects that do not work. For two-player mode, MZ-700 users should reconfigure the second player’s controls, as the default use the number pad.


Numbertron was inspired by a Windows 3 puzzler named Gold Monkey, which was in turn inspired by a Unix game called Greed. I liked the concept, but I thought it would be much more interesting if it had multiplayer and some extra features. Originally I wanted the game to feature a four-player mode, but realistically speaking you’ll probably have a hard enough time convincing one person to play this with you, let alone three! So I gave that idea up.

If you do have the chance, though, play it in two player mode. It does work pretty well, and gameplay becomes a lot more tactical and interesting with an opponent (or co-op parter, if you want).

The game was developed over a number of months, though I usually didn’t work more than a few hours a week on it. I had a playable version up and running pretty early, and I probably spent more time on the menu and various other features than actual gameplay. Naturally I had some neat ideas later on that never made it into the game – ironically, the design of the main menu, which I’m otherwise rather proud of, prevented some of these features from being added as there wasn’t any room for new toggle switches!


Numbertron was created by Joachim Froholt, with testing help from Ben Coffer and David Froholt. It was released as a Patreon-reward in 2019.

You may also want to check out my older game, Minesnake, though I am (slowly!) working on a much improved sequel.