 Enterprising programmers were able to produce games for the ZX81 using nothing more than text characters and the machine 's limited text <unk> . Some ZX81 games achieved lasting fame , such as 3D Monster Maze , a tense first @-@ person perspective game that involved the player escaping a labyrinth with a Tyrannosaurus rex in pursuit . Written in a combination of BASIC and machine code , its innovative design led it to be hailed as the first home computer 3D game and a landmark in the history of computer and video games . 
