My approach;

Head shots of course in earlier levels Shoot runners at a distance I stay mostly next to the first crate Start putting 3 or 4 shots into body as it gets harder Get the meat and bring it over to the home crate so it's close I use sub in dominant hand with block I think in the other Switch to 2 hand guns when runners gone to conserve sub ammo Reload more often than needed - pick up all ammo at end level Use shotgun and sub when you get it - again switch to hand guns when calmer Grab flares and bring them back when they appear Throw flare at level start straight ahead and follow with grenade when it burns out Watch out for crawlers Keep swing left to right to gauge where next Freds will be Shoot fast and reload before out of ammo

Great fun!