No Pain, No Gain Achievement in Halo: The Master Chief Collection

This achievement is in fact retroactive and will unlock if you have already completed any of the many missions in a Campaign’s LASO playlist. As some players have reported however, such retroactive progress will cause the achievement to be stuck at the “Done! Unlocking…” phase in the Xbox One’s achievement app. If this happens, you will need to simply wait until the achievement finishes unlocking itself (this may take days or weeks to happen).

If you have not already met the criteria for this achievement, you will need to complete a Campaign mission from Halo: CE, Halo 2, Halo 3, or Halo 4 with that game’s LASO playlist skulls activated. While some players have reported that completing Halo 2’s “Armory” mission with the LASO playlist skulls activated will unlock this achievement (or even Halo 3’s “Epilogue”), this method is not working for everyone.

If you are one of those who cannot unlock the achievement in such a way, you will need to find another mission and power through it with the appropriate skulls. Halo: CE’s “Keyes” or Halo 2’s “Uprising” both have extremely beneficial exploits that can skip more than half of the mission. As such, it’s suggested to learn the “Keyes Bump” or Uprising’s “early level finish” exploit in order to then complete these missions with the Campaign’s LASO playlist skulls activated. If you are successful in performing this feat, this achievement will then unlock.