Made by crackers and a lot of anti-protection-mechanics. So a long time this game was not cracked.
Example: all tracks are not starting at the same place like normally - every track starts somewhere else. therfore they 

Perhaps the first shoot-em-up with joystick, keyboard and mouse-control. 

There were build in civil vehicles. If you shoot on them and destroy them you loose points. 
If you hit the ambulance your score is 0!

 

The progress could be stored on the game disc! (The game has 35? levels)

come in with your original. come back in one hour. you get the original and  the cracked game back on floppy disc.