The easiest level to do this is Raisin a ruckus. The first 2 enemies can easily be defeated if you wait for the one enemy to move up the right hand side. turn invisable and take out the one on the left(using rb)then take the one on the right. The next two enemies will be near the cliff which you can just sneak past (again using rb)the next enemy is very simple, just wait for him to turn around and sneak up to him on the bridge. The final enemy will be walking in a circle formation shortly after the other one. Again utilise the invisable cloak to sneak up behind him.
All you have to do then is finish the level. Hope that helps. Happy Hunting