quality:corruption
Style

Virtually from the beginning, McCay innovated with the forms of his chosen media. He varied the size and shape of comic strip panels for dramatic effect, as in the second instalment of Little Nemo (October 22, 1905), where the panels grow to adapt to a growing forest of mushrooms. Few of McCay's contemporaries were so bold with their page layouts. Near-contemporary George Herriman with Krazy Kat was the most notable example, but it was not until a generation later that cartoonists such as Frank King with Gasoline Alley, Hal Foster with Prince Valiant, and Roy Crane with Captain Easy attempted such daring designs on their Sunday pages.

McCay's detailed hatching and mastery of perspective enhanced the illusions in his drawings, particularly in Little Nemo. Fantastic grotesqueries such as what McCay witnessed during his time at the Wonderland and Eden Musee appeared often in McCay's work. McCay was noted for the speed and accuracy with which he could draw; crowds of people would gather around to watch him paint billboards.

McCay had a taste for the ornate. The architecture he drew was inspired by that of carnivals, the 1893 World's Columbian Exposition in Chicago and the detailed illustrations in British illustrated newspapers The Illustrated London News and The Graphic. The Maison Quantin of Paris published a series of illustrated books called Images Enphantines, whose pages bear a striking resemblance to McCay's early Little Nemo strips, both in their graphic sense and their imaginative layouts.

To Canemaker, McCay had an "absolute precision of line" akin to those of Northern Renaissance artist Albrecht Dürer and 19th-century French illustrator Gustave Doré. McCay drew with Higgins black drawing ink, Gillott No. 290 pens, art gum, a T-square and angle, and an assortment of Venus lead pencils. In his early magazine cartoons McCay often painted in gouache.

McCay used metafictional techniques such as self-referentiality in his work. This was most frequent in Dream of the Rarebit Fiend, where McCay sometimes put himself in the strip, or had characters address the reader. Sometimes characters become aware of the strip itself—a jealous lover tears the very strip apart in which he appears; another character fastens panel borders to his strip when he realizes the artist has forgotten them; and in a Sammy Sneeze episode Sammy's sneeze destroys the panel borders.

In contrast to the high level of skill in the artwork, the dialogue in McCay's speech balloons is crude, sometimes approaching illegibility, and "disfigur his otherwise flawless work", according to critic R. C. Harvey. This is further highlighted by the level of effort and skill apparent in the title lettering. McCay seemed to show little regard for the dialogue balloons, their content, and their placement in the visual composition. They tended to contain repetitive monologues expressing the increasing distress of the speakers, and showed that McCay's gift was in the visual and not the verbal.

In his comics and animation McCay used stock ethnic stereotypes common in his era. A conscious attempt to offend is not apparent. He depicted blacks as savages, or wishing they could be white. Most prominent were a pair of characters in Little Nemo: the ill-tempered Irishman Flip and the rarely speaking grass-skirted African Little Imp. In the animated Little Nemo, the Anglo-Saxon Nemo is shown drawn in a dignified Art Nouveau style, and controls by magic the more grotesquely caricatured Flip and Imp. Women were few in McCay's work, and were depicted as superficial, jealous, and argumentative; the Princess in Little Nemo never partook in the camaraderie the males shared.