I'm pretty sure that the emotions here are a reference to Super Princess Peach. The commentary uses the word "喜怒哀楽," or kidoairaku, for emotion instead of the much more common "感情." Each of the four kanji in kidoairaku corresponds to one of the Vibes in Super Princess Peach (and here): 喜 for Joy, 怒 for Rage, 哀 for Gloom, and 楽 for Calm. Plus, the Vibe Gauge in the Japanese version of SPP is called "喜怒哀楽ゲージ", so yeah.

Which brings up a question: Does an image count as a crossover if it shows gameplay mechanics, but no character? I know that it counts for UI stuff, like in this comic by goma (gomasamune), but I don't think I've encountered direct references to gameplay mechanics themselves before, at least not ones unaccompanied by some UI element.