Look at the piano score in the first panel. Intense. Schulz had been quoted as saying he took time to make the scores accurate and loved how they looked on the page. Keep in mind, at this point Schroeder has only said a couple of words, yet he's already titling his compositions.
Another subtle innovation in these strips is a recurring gag template for Peanuts, the blatantly bizarre thing that is somehow real that the other characters can react to. Snoopy is a particular focus for these kinds of shenanigans later (I remember the "whirlidog" sequence, coincidentally also featuring Schroeder), but Lucy gets into some of it too. It works best if the bizarre character possesses an elemental, "force of nature" style of personality for it's a good way to illustrate their strength of will, by presenting it as triumphing over reality itself.
