Bulletstorm: Full Clip Edition

See Supernova Achievement. You should ding this while working on that one. Otherwise in Echoes mode you'll see the top of every page has a line that says "Score" that's the accumulative score of all echoes you've completed. Try your best on every echo and you'll eventually get here. Try to maximize your points on every level with using as many unique skill shots as you can and don't forget you have skill shots related to kicking/leashing/thumping/environment besides the standard weapon ones. You can couple a lot of the weapon ones with thumping.

This will come naturally, normally half way through the second page of echo maps, unless you're on a stream of getting 3 stars on every map, you can be lucky enough to have it before the end of the first page.