Tricky x US English - 9/15
Difficult x US English - 9/15
Fiendish x US English - 3/15
Tricky x British English - 12/15
Difficult x British English - 7/15
Fiendish x British English - 3/15
Tricky - 13/15
Difficult - 10/15 (I didn't hear some of the words, and the repeat function wasn't working)
Fiendish - 6/15
British English:
Tricky - 12/15 (Could've possibly been 13/15 if I heard one of the words, I didn't even attempt the word I didn't hear)
Difficult - 9/15
Fiendish - 6/15
Oh, looks like I suck at spelling in both forms of English.