StarTropics (1990) is the one where Nintendo broke the fourth wall and reached into your physical world. You play Mike Jones, a kid from Seattle searching a chain of tropical islands for your kidnapped archaeologist uncle, fighting with a yo-yo in a top-down adventure.

It's an unusual game in the catalog because it was made for us and not for Japan. Nintendo's Redmond office drove the design, the humor is American, the hero is an American teenager with a baseball bat and a yo-yo, and the game never got a Japanese release at all.

The dungeons don't play like Zelda's either. Inside them, Mike moves square to square on a grid rather than freely, and most rooms are a puzzle about the floor: tiles that sink after one step, platforms that slide, gaps you cross by jumping from one exact square to another. It's closer to a block-pushing puzzle game with combat in it, and it gives the whole thing a rhythm nothing else on the console has.

Its legend, though, is one moment. A character tells you to dip his letter in water to get a code, and players hunted through their inventory for a letter that wasn't there. The game shipped with an actual folded letter in the box, and the number 747 was printed on it in invisible ink. Dunk the physical paper and the code appears. No internet, no hint line that would admit it, just you and a wet piece of paper on the kitchen counter.

Anyone who bought it used, or rented it, was simply stuck. Nintendo's own Power Line got the call constantly.

A charming, weird, very Western Nintendo game. That letter trick is one of the greatest packaging gags in the medium.