That is the original game’s intentional quirky branding. The family in the game is named "Lemomnon" – a pun on "lemon" and "mammon" (greed). So "Lemomnade" is correct in-universe.
: A distinct art style that is often described as "crisp and colorful," designed to match the refreshing theme of the title. lemomnade family squeeze latest v111 by mt hot