An unnamed programmer, "The Hanafuda Captain", hid a message in the NES Classic Edition's code that reads:

"This is the hanafuda captain speaking. Launching emulation in 3...2...1. Many efforts, tears and countless hours have been put into this jewel. So, please keep this place tidied up and don't break everything! Cheers, the hanafuda captain."

"Hanafuda" is a reference to the playing cards Nintendo sold before entering the video game business.