My favourite was using SoftICE to crack itself, but I learned a lot about debugging and low-level coding via +fravia's writeups, amongst others. It helped that

My favourite was using SoftICE to crack itself, but I learned a lot about debugging and low-level coding via +fravia's writeups, amongst others. It helped that when I was a teen one of the reasons I got interested in programming, and assembly language, wasn't so much to create new "things", as it was to cheat at games. The first step was always removing the copy-protection stuff, so you could access the game code. Then you could explore and patch the binaries for infinite lives, health, & etc. I've still got some printed magazines from the 90s where my POKEs were printed for ZX Spectrum games.