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A few weeks ago, I fondly recalled the ZX81, a tiny computer that set many of us off on this weird and wonderful journey into hobbyist technology. This week, I'm taking a quick look at one of the most influential titles ever published on that machine: 3D Monster Maze.

Since we're about to see the release of a new Doom title, it seems fitting to feature the granddaddy of all first-person games. 3D Monster Maze took my breath away when I saw it for the first time. I had a ZX81 with a 16KB RAM pack, but all I had to play were things I created myself (getting the pound sign to move across the screen before it crashed!) or one of the many educational titles that my parents bought.

3D Monster Maze was something entirely different though. After waiting for it to load and reading through the intro, you'd finally find yourself trying to find your way around the maze before the T-Rex located you and had you for breakfast. It was amazing - at least to a ten-year-old me, anyway.

After you mastered being hunted down by a dinosaur, the real challenges of 3D Monster Maze began to surface. The ever changing maze, trying to map out each maze as you went (in case you had to redo the level!), trying to keep one step ahead of the T-Rex to rack up as many points as possible and attempting to hack the BASIC portion of the game to increase its speed.

3D Monster Maze was programmed by Malcolm Evans from an idea by JK Greye, in 1981. The game was eventually finished and ready for publication early in 1982, by JK Greye Software for the ZX81 with the 16KB RAM pack.

Evans was a former aircraft designer and later a microprocessor scientist. After receiving a ZX81 for his 37th birthday from his wife Linda, Evans began to test the machine's capabilities and focused on developing a routine that could effectively stretch the computer to its upper limits.

Although the ZX81 was called primitive and suffered from a monochrome display, terrible keyboard and no sound, it was the foundation that Evans worked on, and he managed to create a game with a mixture of Assembly and BASIC, using randomly generated 16 x 16 square mazes.

Originally the maze was a top-down view, but Evans, having already been told that he was too old to go into software, created a new routine that generated a point-of-view of someone actually inside the maze.

According to legend, Evans met up with Greye at a classical guitar club in Bristol. Greye was just forming a software publishing company, and in passing Evans mentioned his maze routine. "Has it got a monster in it?" Greye asked, so Evans created the tyrannosaurus and the story around its re-animation. The rest, as they say, is history.

Intense gameplay, great problem solving and a very atmospheric game. The stuff of nightmares and the rise of 3D technology on home computers.

Getting lost and getting overexcited when being chased by the T-Rex and knocking the 16KB expansion block to crash the ZX81.

A wonderful game and one we'll fondly remember forever. Thank you, Malcolm.

1. Evans also created the Trashman games on the Spectrum.
2. The T-Rex was copied from a children's book of dinosaurs.
3. Evans created the graphics on graph paper, then into data and his wife typed it out into the ZX81.
4. Apparently, everyone who test-played 3D Monster Maze got stressed as the T-Rex started to hunt them, apart from Evans' wife, who simply started laughing.