Mike Mika, the developer who had modded Donkey Kong so his daughter could play as Pauline rescuing Mario did just that. Mika hid a marriage proposal into a Game Boy Colour port of the Atari puzzler Klax. However unlike the Donkey Kong mod which he made for his daughter, the Game Boy Colour was a commercial product. Even for funny is that Mika’s then girlfriend took years to actually play the game and finally uncover the proposal. In a video interview to Wired, Mika recalled the entire episode and had a good laugh.
Mika said”She loves puzzle games, I’m doing a puzzle game now, so let me just put that out there and she will find this thing in the game,” he said of his thought process at the time. “I leave the Game Boy out, I urge her to play it, and she never picks it up,” he laughed. “This goes on for literally, I think, almost like years now. It was like three years.” “So do I propose to her normal, or I have this thing here that’s really cool, but I can’t get her to play it, ever?” he said.