In Calvin and Hobbes, Sunday comics often feature more outlandish scenarios than the weekday strips, and are less reliant on punchlines and gags than the expression of artistic license. This is consistent with Bill Watterson's insistence that syndicated comics should be treated as a serious art form as opposed to vapid, pandering commercial hackwork.
In the strip's later years, particularly starting with the first sabbatical and subsequent change in format, Sunday comics upstaged story arcs. As the latter dwindled in frequency, the focus on Sunday strips became narrower. Spaceman Spiff's appearances were relegated almost exclusively to the larger Sunday format from 1991 onward. Moreover, the comparatively stiff, restrictive structure of the earlier Sunday strips was dropped in order to make way for more unorthodox layout designs.