This small book will tell its reader, first of all, a fan of the home computer of the 80-90s ZX Spectrum, how you can change the game code in such a way as to win in any case - by setting an endless life for this, making the hero invulnerable, or blocking the timer time restrictions. How to do this is another question. That is why the book is divided into two parts. The first part describes the structure of the computer operating system, how it organizes memory and stores information, including information loaded from a magnetic tape or floppy disk. The reader will get acquainted with the basic techniques for hacking the ZX Spectrum using simple inserts in machine code, or small sections of code in BASIC. All this knowledge will be useful in entering “immortality codes” - special values for certain memory cells, which will later make your favorite game on the ZX Spectrum passable without much effort.