I beat halo reach on laso and haven’t gotten the achievement. I wanted to do a playthrough on halo 1-4 and beat them all on laso but I don’t want to do that if I can’t get my achievements. It took me days just to beat the game on laso but I finally did it and I don’t even have an achievement to show for it. Is there any way I can get the achievement without doing it all over again?
Start by checking the playlist in the in-game menu.
Does it say you completed all the levels in the playlist?
If yes, I’d suggest you find someone who is on the final level, and join them to replay it. The achievement checks for playlist completion every time you beat the last level, so if all the other levels are done, just beat that one again.
Now, if you check the playlist in-game and it shows something missing - well you have your answer.
Find someone who is at the level you are missing and join them to beat it.
Then do what I outlined above for the final level.
And always try to make sure you are connected to the internet.