Karateka (Commodore 64)

Karateka
Developer: Brøderbund Software Publisher: Brøderbund Software Platform: Commodore 64 Released in US: 1985 This game has anti-piracy features.

Anti-Piracy Features

Please elaborate. Having more detail is always a good thing. Specifically: How are these actually triggered?

To do: List the effects of the routines which do not have the effects listed.

The game has multiple routines related to copy protection, taking a minefield approach to anti-piracy:

1. A routine that checks one byte, which scrambles music.
2. A routine that checks one byte, which makes playing by the keyboard impossible.
3. A routine that prevents the player from walking through a door.
4. A routine that increases the opponent's regeneration.
5. A routine that makes the hawk invulnerable.
6. A routine that prevents movement when facing the final opponent.
7. A routine that crashes the game when played on an NTSC system.
8. A second routine that prevents walking through a door.
9. A routine that is active before the game loads the levels.