Can't do this consistently. Anyone figure out the trick?

I'm typing this because I'm about to give up finding out how to get the achievement "Upgraded!". I just don't know where else to look for it. By now i finished all the levels (33/33), got all the collectables (33/33) and finished all the secrets (31/31). Therefore I already unlocked every single achievement except "Upgraded!". Does anyone have a hint for me on this one? ;)...

i saw the screen shot how u do it?????

finished lvl 4 two times with controls reversed but didn't get the achievement... ;(

Is it too violent?