Terry, their only true AC/DC sound-alike album is 'One Vice At A Time' ('Long Stick Goes Boom', 'Bad Boys, Rag Dolls'), which happens to be one of their best. Their big 4 albums, 'Metal Rendezvous' ('80), 'Hardware' ('81), OVAATime, and 'Headhunter' ('83; w/ 'Screaming in the Night'), all sound distinctly different and are excellent top to bottom. After that they went into more of a glam direction with 'The Blitz' and 'Change of Address' before trying to get back on track with 'Heart Attack' in '88. Their two post-reunion albums ('Hoodoo' and 'Dirty Dynamite') with the classic core of Storace, von Arb and von Rohr all back on board are very good and sort of an update on the 'Hardware'/'One Vice' era. There is an 'Original Album Classics' boxset with 'Metal Rendezvous', 'Hardware' and 'One Vice' https://www.amazon.com/Original-Album-Classics-KROKUS/dp/B008OX3XOA/
which can be had for around 10 bucks on Amazon. That and the Rock Candy re-issue of 'Headhunter' are the Krokus essentials on CD.