If you wan't your hard badge I highly recommend to start game with very easy difficult and ending by escaping by helicopter. Choose your best 5 survivors (you can specially play longer to make your survivors level 10) then starting game with new difficult (seriously hard or impossible difficulty) with 5 high skilled survivors instead of 5 beginners (:
 "Pandemic 2"){kind=icon}
 "Rebuild 2"){kind=icon}
 "GemCraft chapter 0"){kind=icon}
 "Burrito Bison Revenge"){kind=icon}
 "Musaic Box"){kind=icon}
 "Knightmare Tower"){kind=icon}
 "Infectonator 2"){kind=icon}
 "Decision 2"){kind=icon}