The “100-” in the filename likely refers to a —the original release build, before Croteam released subsequent patches. This is a critical distinction: cracks were version-specific. Applying a v1.00 crack to a patched or updated game installation would almost certainly fail.
A marketing tag used by uploaders to claim that this specific release successfully bypassed the "Immortal Scorpion" trigger and other late-game glitches.
: Serious Sam 3 includes a native "Play Moddable Version" option on Steam, which allows for deeper customization and community-made fixes, though it disables achievements. Official Cheats