Killer pieces
These achievements are self explanatory 
In order to get them play live games (rated or non rated) and:
- deliver checkmate with a pawn -> you get Killer Pawn
- deliver checkmate with a knight -> you get Killer Knight
- deliver checkmate with a bishop -> you get Killer Bishop
- deliver checkmate with a rook -> you get Killer Rook
- deliver checkmate with a queen -> you get Killer Queen
