Someone has coded the famous Atari game ‘HERO’ for the ZX81. Hats off to them, for this awesome conversion.
48Kbyte Hires-compatible RAM Expansion
The cassette file fits into 16Kbyte, but after decompression it will occupy around 27Kbytes, and additionally requires 6Kbyte bitmap memory, plus an 8Kbyte buffer for horizontally pre-shifted foreground sprites.
Joystick (wired to A12 line in keyboard matrix)
The game can be also played via Cursor or Q,A,O,P,Space keyboard keys, but a joystick will greatly help to control the game.’