No Pain, No Gain

No Pain, No Gain is an achievement in Halo: The Master Chief Collection. It is unlocked by completing one mission with the LASO skulls enabled. The achievement is worth 10 gamerpoints.

This achievement is not unlocked by playing The Heretic or The Armory in Halo 2: Anniversary, Arrival in Halo 3, or Prologue in Halo 4. It also cannot be unlocked in Spartan Ops, likely because Spartan Ops does not feature the Iron skull.