Hello, i tried following the other achievements guide but the decaps achievements cant be done with knights as the other guide says, Decaps only counts if you cut the head with something like a sword ...... etc

The easiest class to get this with is Guardsman with his main weapon, from my experience i had a more successful rate making decaps if my enemies are on either left or right of my screen i always make sure i can hit 2 enemies with 1 swing.

I hope that helps.

Crysis Regards