Time stopping, or Hitstop you basically set the Time.timeScale in Unity to 0. then set it back to 1 after a split second. Alot of games like Street Fighter, Hollow Knight etc use this to make hits feel more impactful. stopping time for a split second when the player gets hit also gives the player time to recollect themselves and quickly think of a way to get out of a tough spot.
In general it really adds a heavy punch to each hit and makes it feel more satisfying
