I'd say that even though a lot of the guitar construction was really basic with chords thick featuring heavy distortion, Chuck created riffs that were tremolo picked, chords fitting the vocals as well as their content, and solos by the man plus James Murphy in the lead department also brilliantly executes his efforts. The lyrical content was more thought out than the first 2 Death albums. But "Leprosy" has some good songs with really memorable lyrics especially for the song "Pull the Plug".
Chuck was still developing on his leads while James Murphy was more melodic during his featuring tremolo picking galore, sweeps amazingly played out, and arpeggios fluent entirely. I think that it was a wise move to have this album remastered to really get the most out of it and recognizing that way back in 1990, the production quality wasn't as good obviously plus Death was still getting established with their sound just different lineups with each succeeding record.
Chuck worked with some really amazing guitar players and James Murphy here on "Spiritual Healing" is an example of a man that was wicked in the lead department. He also suffers with brain cancer like Chuck and that is why there is Sweet Relief Foundation for musicians that are without medical insurance. Back on the topic of "Spiritual Healing" as an album, Chuck had really deep throat which fit the guitar chords and progressions quite well. A lot of people feel that this is Death's best release ever. To me "Human" is, but it's still debatable.