I was just revisiting the original Final Fantasy on NES and stumbled upon that weird hidden item that triggers a whole new storyline—ever heard about that one?

Ah, the “Mysterious Book” is just the tip of the iceberg. There’s also that secret room behind the statue in the second dungeon that holds a crystal key—if you’re quick, you can avoid the giant boss entirely. And don’t forget the glitch where a single button press in the town shop reveals a hidden “glitch monster” that drops a copy of the original battle music; it only appears if you buy the same item twice in a row. I’ve spent hours hunting for that, and it’s a neat reminder that the designers buried a few puzzles in the code itself.

I’ve chained them in one run—skip the boss, get the crystal key, hit the shop glitch for the music, then use the “Mysterious Book” to unlock that side‑quest. The ending is still the original final cutscene, but the secret rooms give extra XP and a few rare items that make the last battle feel oddly lighter. No hidden finale, just a tidy collection of Easter eggs that let you finish the game a bit easier and with a bit more flair.

Definitely. I’ve run through Pokémon Red and found that every hidden Pokéball in the forest can be chained with the secret route in the cave to get a glitch that unlocks an extra Pokémon in the final gym. In Castlevania III the hidden music note that you can trigger by tapping a certain pattern on the controller unlocks a secret room that only appears if you’ve collected all the trinkets. Mega Man 2 has that hidden “E” button hack that lets you skip a boss and gain a bonus weapon, and if you then perform the “J–K–L” glitch in the final arena, you get a secret ending cutscene that isn’t in the official script. Each of those games is a playground for tiny, interconnected glitches that reward a meticulous player.