Using a downloaded 100% save file will not get you banned from Steam. If you want the corresponding Steam achievements to unlock automatically upon loading the file, follow these rules:
The Ultimate Guide to The Binding of Isaac: Repentance 100% Save Files binding of isaac repentance 100 save file
"You are skipping the journey. The game is about unlocking power through suffering. Using Tainted Cain without earning him invalidates the experience." Using a downloaded 100% save file will not
Some gameplay-altering mods create their own custom save states. Turn off your mods via the main menu, restart the game to confirm the 100% save is active, and then re-enable your mods one by one. binding of isaac repentance 100 save file
You want to test complex mod setups, custom characters, and item synergies with the entire vanilla pool already unlocked.