As well may bulwark, keelhauling, smearcase, and still life be derived from the German words Bollwerk, kielholen, Schmierkäse (in which the pronunciation of the a also is closer), Stillleben.
Thought forlorn was of German origin, too, but learned better now.
But I dont think you are correct about the other ones. A lot of words are nearly the same in german and dutch, but what counts is what language english got it from. You can compare some words english took from french, you could say no they come from latin, if nearly the same word excist in latin. But if they havent borrowed it directly you would say they got it from french.
(that is the reason some words are borrowed twice with a long period of time in between, so one of the words have evolved. You end up with two similar words with different meanings. Very interesting :) )
EZEL - means donkey or Jackass
IJZEL - means easel
Though I would like to point out to the one who made this quiz that when translating a verb in its infinitive form (Du. hele werkwoord) you cannot use the -ing form.Therefore the answer to kielhalen should not be 'keelhauling', but 'to keelhaul'.
Vast = Secure(d) [I have no idea what avast is]
Verloren = Lost, (not forlorn)
Smeerkaas = Cheese spread (not smearcase)
Trekker = A Hiker - someone who hikes, (not trigger)
And the best translation of Rugzak is Backpack!
avast is obviously the antivirus program. No seriously it is a nautical term (coming from dutch hou vast).
I think you kind of missed the intention of the quiz