This is cumulative.
Easy way to get this quickly is in Old Town Level 7.
About mid through the level you will come to a zip-line behind a window.
Jump though the window, zip down and jump through the second window at the bottom. Then just die.
You re-spawn in the room at the top of the zip-line with both windows intact. Rinse and repeat, takes about a minute or two.
Edit4: Everyone commenting on my solution report, that "Cannot be missed" could be inaccurate. Change my mind?
Edit: This cannot be missed if you play the game a little longer. It should pop naturally midway through world 2, District Null.
Edit2: Iggsy81 and Rookie68 report, that the Achievement did not unlock for them. Might be glitched for some.
Edit3: Gerbasgamer reports, that he/she completed the game without the achievement popping. Using my solution worked, though. Strange.