T-Zero: inverted joystick handling and "PIRATE" written in the highscore list if game is not cracked properly
Kick Off 2: "random" crashes if game is not cracked properly
Sleepwalker: impossible to finish level 1 if game is not cracked properly
Fire'n'Brimstone: graphics trash due to screen memory used as MFM buffer in the cracked version
There are many many more examples.