Age of Grinders is a video game Jake and Finn play in "Flute Spell." It appears to be a convoluted turn-based role-playing fantasy adventure, similar to games like the original Final Fantasy in design. It takes up so much of BMO's memory that it does not have a save feature, and automatically resets if the user tries to have a conversation with BMO while the game is running. Finn and Jake eventually beat the game working in tandem, at which point Finn declares it "bad and boring" and "just what I needed" to take his mind off his lady drama.
In "Flute Spell," Finn discovers that the only main objective in the game is to upgrade your armor and defeat minions.
- The name refers to "grinding," a term gamers often use to describe repeatedly doing tedious tasks necessary to advance in a video game, such as battling monsters to get gold and experience points to level up.
- The game is an obvious parody of the Phantasy Star franchise, drawing visual elements from the fourth installment and its name being derived from Phantasy Star 2, which was grind-based in nature, requiring hours of leveling to be able to defeat certain bosses easily.
- One of the characters in this game, Ako, shares the same name with Ako Castuera, who is a storyboard artist for the series.