09 Jan 2015 09 Jan 2015 08 May 2015
As of 1/8 you can get this by going into Spartan Ops and selecting each chapter. Start the level and once you take control of your character you can quit and it will save progress as completing that level. Do that for each chapter/level and this achievement is yours.
Get this before they patch it!!!
As of 05/2015 the April patch took away this glitch. Unfortunately you might have to actually play the levels now. I will update the solution if someone finds a faster way. Thanks