hard mode

noun2

1. •
   A game mode with a higher difficulty than the standard gameplay.

   • If you’re playing on hard mode, be warned that zombies can break down wooden doors. — 2014
2. •
   (figurative) A task or situation made deliberately more difficult than usual, often as a test of skill or endurance.

   • But just when I thought I’d gotten the hang of things, a snake chased me into a deeper level of the labyrinth! Everything’s on hard mode down here. — 2018