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This site has an impressive collection of in-game anti-piracy measures that is worth checking out [1]. From Donkey Kong Country 2 (SNES): Checksum Verificatio

This site has an impressive collection of in-game anti-piracy measures that is worth checking out [1]. From Donkey Kong Country 2 (SNES): Checksum Verification - At the beginning of a level, a checksum is run on 544 bytes worth of code and data which includes all of the above tests, the PAL/NTSC region check and various initialization routines. If the checksum generated doesn't match the hardcoded value it compares against (i.e., the anti-piracy routines were tampered with), RAM address $7E0AFD, which holds the total number of screens in the level, is decremented by one. This punishes the player by causing the screen to stop scrolling just before reaching the goal in a level.[2] It's so brilliant, yet so evil. [1] https://tcrf.net/Category:Games_with_anti-piracy_methods https://tcrf.net/Category:Games_with_anti-piracy_methods [2] https://tcrf.net/Donkey_Kong_Country_2:_Diddy%27s_Kong_Quest_(SNES) https://tcrf.net/Donkey_Kong_Country_2:_Diddy%27s_Kong_Quest...

GlitchMr 8y ago
Hm, interesting. Long time ago, I intentionally tried cracking games to detect anti-piracy methods, and Donkey Kong Countrty 2 was one of those, and I triggered the empty SRAM check while doing so (and added that to the TCRF page). I checked the game with more SRAM than the cartridge normally has, and... nothing??? Checking that is a very typical routine in SNES games, and yet... I simply assumed due to that it's the only check, and an incompetent one at that -- first, it would be more evil to let the game continue with no save RAM only for saves to not work, second, why not check for more RAM. But then it turns out there are actually were more anti-piracy methods, and they are quite evil. Wow. I'm not surprised I did not find those considering how those worked however, I had no reason to change the ROM to add a crack intro.

GlitchMr 8y ago

Hm, interesting. Long time ago, I intentionally tried cracking games to detect anti-piracy methods, and Donkey Kong Countrty 2 was one of those, and I triggered the empty SRAM check while doing so (and added that to the TCRF page). I checked the game with more SRAM than the cartridge normally has, and... nothing??? Checking that is a very typical routine in SNES games, and yet... I simply assumed due to that it's the only check, and an incompetent one at that -- first, it would be more evil to let the game continue with no save RAM only for saves to not work, second, why not check for more RAM. But then it turns out there are actually were more anti-piracy methods, and they are quite evil. Wow. I'm not surprised I did not find those considering how those worked however, I had no reason to change the ROM to add a crack intro.