Twain thought that the explosive conclusion to CY was funny, when it seems
more horrifying than amusing to most contemporary readers.  Two of the best
essays I can recommend on CY, both touching on this issue, are Ann Douglas,
"Art and Advertising in CY: the 'Robber Baron' Revisited," _Canadian Review
of American Studies_ 6 (1975): 182-195 and Judith Fetterley, "Yankee
Showman and Reformer: The Character of Mark Twain's Hank Morgan."
_Texas Studies in Literature and Language_ 14 (1974): 667-79.  For a very
dark view of Twain's conclusion, see David Ketterer, "Epoch-Eclipse and
Apocalypse: Special Effects in CY."  PMLA 88 (1973): 1104-14.