Your sensory boost is activated by using you dash
midair. To get this achievement, you must kill 10 enemies in one life without taking advantage of this. I found the easiest level to do this early on is level 5, the first level that introduces the powerup that slows everything down. That way you can kill enemies while they are almost defenseless. Another spot that is really good is the third to last level that is good for quite a few achievements. Earky on in the level there are lots of spiders to kill, and getting 10 should not be a problem.