Here is my 100% Achievement guide and full walkthrough so you don't miss a thing.
You first get the Dashing Ability after Level 6 - Aliens Stole My Brain Stem.
To use it, just simply press
and as is in the name, Crypto does a little dash.
The first time you encounter soliders with Rockets is Level 11 - Tower Defense.
Just like the ship, you'll see when a rocket is coming towards you with an icon on screen that gets whiter the closer it gets to you.
As soon as its about to hit you, press
to dash away, achievement unlocked.
Go to 2:28:10 in my part 1 video to see where and how to unlock this
Hope this helps!
Part 1
Part 2