More of a Tip, than a guide:
This one did NOT unlock for me. I finished the game had all the achievements, except for this one.
So, after starting a New Game+ and doing the first 10 levels for the one that was supposed to be my last achievement, i did Not stop at level 10, and kept playing until level 42 (on New Game+), immediately after finishing this level (for the second time) it popped.
Dunno if it was just my game, or if its going to be a common problem, just letting people know that it might glitch,but its not Unobtainable.