I've only ever played the first episode. I remember there was an external program that would catalogue the items you had found but you would have to save, quit, scan, and reload. The completionist in me didn't mind the interruptions to gameplay at the time.
The first episode was free, acting as a demo for the saga of four. It was fun, and the dog companion was a neat addition to the Diablo formula. I think you can still purchase the episodes from the original developer but it would be amazing for it to be here, preserved on GoG as a complete collection.