Hardcore

From Mass Effect Wiki

Hardcore is the penultimate difficulty setting. It must be unlocked by completing one playthrough on any difficulty. While playing on Hardcore:

• Most enemies are scaled up based on player's level
• All enemies have protection
• Bosses have immunities

Once a playthrough on Hardcore is complete the Insanity difficulty is unlocked, provided the difficulty is not changed at any point (with the exception of aboard the Normandy BEFORE EDEN PRIME). Completing a Hardcore playthrough will also unlock the Distinguished Combat Medal worth 25 gamerpoints. As an additional reward you will also unlock a Saren gamer picture.