Death Squared

Playing Story Levels 1-9 is the easiest method to unlock this Achievement. If done properly, this and “Cleaner Run” can be unlocked in around 3-4 minutes.

Here is a guide I found on YouTube:

Hey everyone, just a quick video showing how to get all the Clean runs achievements, and the Hard work wasted. Hope the video helps!

You can find videos of the solutions on YouTube if you need them obviously, but they are simple enough to memorize after 1 or 2 attempts but a little trick that helped make this easier was that the 9 levels don’t have to be sequential nor do they all have to be Story levels, they can be split between Story and Party. So what I found to the be easier than completing the first 9 Story levels was to complete level 6 of Story which I think was the trickiest of the 9 levels to get it out of the way first, then Pause and Exit. If you end up dying, make sure to Pause and Exit and then relaunch the level. Then I completed Story levels 1-5, Pause and Exit. Then lastly, Party levels 1-3. Also, if you happen to move one of your cubes off the ledge accidentally, if you are quick enough, before the cube explodes below the level you can Pause and Exit that level and relaunch it and you will maintain your perfect streak. This happened to me on my final attempt when I got the achievement.

Here is yet another video on how to get cleanest run achievement guide!