[The Sunshine Boys is a play] where gagwriting is ostensibly subordinated to pathos, and underlying the comedy is a supposedly serious theme…. The significant plot concerns a once famous vaudeville team, Lewis and Clark…. (p. 444)

The story is exiguous but presumably will serve as scaffolding for the exploration of such great topics as What Was the Glory of Burlesque?, Where Has That Old-time Humor Gone?, What Is to Become of Beloved Entertainers Grown Aged?, Is Greasepaint Thicker Than Friendship in the Theater? and Can Man Laugh Away His Mortality? There may be one or several worthy plays in this, but none can survive burial alive under 10-Gags-10 per minute—some new, more old, a few funny, many dreadful, but all of them marching, skipping, somersaulting at you without respite. The humor itself is sternly limited in scope: insult jokes, speaker's-stupidity jokes, geriatric sex jokes, and show-biz in-jokes. Although [Clive Barnes] has compared this alleged comic masterpiece favorably to Molière and Shaw, one glance at Don Juan and the difference slaps you in the eye.

To Simon, the basic unit of playmaking is the joke. Not the word, the idea, the character, or even the situation, but the gag. It kills him if here and there a monosyllable resists funnying up, if now and then someone has to make a move that won't fracture the audience. Note how many lines in Don Juan don't try in the least to be funny—which is why those that really are hit us, and why life and thought are allowed elbow room in the play. (p. 445)