Play Instant Action matches with every mutator, if you have played Deathmatch and used all the mutators 1 per game and you have not got this don't panic as there is 4 more in CTF, Warfare, Duel and TDM. When you finish playing a match with the last mutator the achievement will unlock.
Here is a list and and gamemodes you should play them on as to not get confused. Work your way through this list and you will get it. Remember it is only 1 per match.
Kills Slow Time (Instant Action ONLY)
No Super Pickups