For this achievement I would recommend one of 3 things.
1. Play through whichever playlist of the difficulty you plan on beating the game in first. Theres an Easy, Medium, Hard, and Legendary Playlist.
Then, play the 2 playlists that only have 3 levels each.
2. If you're doing the LASO playlist, same thing.
3. Play the 2 playlists that are only 3 levels, then the one that is 4 levels.
All the smaller playlists are on normal difficulty with 0 skulls on, so it may be a good idea to attempt your speedruns, but some words of warning.
- When I did the 3 smaller playlists, even though I did all levels under par, only a few gave the achievement.
- The third playlist I completed did not give me credit for this achievement for some reason (I did LASO and both the 3 level ones), so I had to do the four level one as well.
I'm not sure what made that happen. I've seen reports of people claiming skipping the cutscenes messes with achievements, but the last level I did was the Maw and it doesn't let you skip that cutscene. If this happens to anyone else I'd like some info.