H.E.R.O. Helicopter Emergency Rescue Operation ZX81 Version ...... download hero zx81 version nocash no$zx emulator nocash homepage Requirements: 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.