1951
Chalkboard drawings of Yoshi seen in message boxes from Yoshi's Island, including those found in the data but not used in the game.
1952
Before playing a course in Super Mario Maker 2, a brief animation of Small Mario in the course's style plays alongside a life counter. In the NSMBU style, Small Mario's right leg (viewer's left) is visibly distorted below the knee. This does not occur during gameplay (right).
1953
Addendum: I apologize for any ambiguity due to the phrasing in the post; the "camera plane" is simply another way to say "the screen". Below are illustrations of what it means for Mario to move parallel or perpendicular to it.
1954
The 1989 commercial for Super Mario Bros. 2 (left) shows an unusual health meter in the upper left. This is actually a feature from the game's prototype version, where pressing Select gives the player 15 health (middle). The glitched health is a recolored part of Mario (right).
1955
In Super Mario Sunshine, the Blooper surfing room in Ricco Harbor uses the secret course "train tracks" skybox, which can be seen by entering first-person view near a wall. The same is true for Corona Mountain, however, this cannot be seen in-game and requires tools to view.
1956
Sprite representing the word "hug", from the Sentence World word suggestion images in the educational SNES game Mario's Early Years: Fun with Letters.
1957
In the files of Nintendo of America's official Mario website, the image depicting a Rocky Wrench calls it "Morty Wrench" instead. This may be a simple error; however, it could be an official name for Giant Rocky Wrenches that has simply not been used in a game before (see text).
1958
The SNES version of Yoshi's Cookie contains a sprite of a Boo with a smug expression that is always partially obscured. I have attempted to create a clear version of the sprite using all available references; however, part of the sprite had to be left to speculation.
1959
"Super Mario Bros. Vol. 3: Mario Corps Sortie", an army-themed 1985 Mario manga/adventure book. The book features military outfits for Mario, Luigi and Princess Peach.
1960
Artwork of a Chain Chomp featured in a North American print ad for Mario Party Advance.
1961
Wario's standard shoes worn with his overalls have had more colors than any other Mario character's shoes throughout the years, having been shades of green, teal, purple, gray, brown and yellow. (This does not include shoes worn with other outfits.)
1962
During Bowser's first scene in Paper Mario: The Thousand-Year Door, there is a painting of him at the far right wall of the room, at an oblique angle to the camera. Moving the camera to better see it reveals that a mustache has been added to Bowser.
1963
Mario and Luigi's "covered with kisses" sprites from Super Mario All-Stars. Supper Mario Broth wishes you a happy Valentine's Day.
1964
In Paper Mario: The Thousand-Year Door, unlocking Ms. Mowz before Bobbery (possible legitimately) makes her glitched in Chapter 5. The healing menu shows Bobbery instead of her, and using an item on her actually heals Bobbery, wasting the item since he is not physically present.
1965
Drawings of Koopa Paratroopas from concept art sketches for Super Mario Bros., drawn by Shigeru Miyamoto. The drawing in the center appears to be from later in the design process and is closer to the enemies' look in the finished game.
1966
Licensed "Pocket Yoshi" T-shirt from the 1993 Nintendo Power Supplies Catalog. A close-up of Yoshi in the pocket is provided.
1967
The 1989 licensed Nintendo Sticker Activity Book included stickers of a variety of Super Mario Bros. and Super Mario Bros. 2 characters, some featuring original artwork. As part of a puzzle activity, the letters in the names of all characters on the stickers have been scrambled.
1968
The European French (top), European Spanish (bottom left) and Italian (bottom right) titles for Mario & Luigi: Bowser's Inside Story all translate as "Journey to the Center of Bowser", referencing the 1864 science fiction novel Journey to the Center of the Earth by Jules Verne.
1969
Cover of a Japanese official guide for Mario Paint.
1970
In Paper Mario, Mario normally has a shadow at all times, visible directly below him when he is jumping (left). However, after sleeping at the Star Haven inn, upon waking up, Mario's shadow will be missing (right). This effect lasts until Mario leaves the area.
1971
An unused scene found in the data of Super Mario RPG is a duplicate of Peach's scenes from Booster Tower on a different background; however, the dialogue is replaced with the time messages from the Count Down boss battle. This is the only unused scene in the game.
1972
@eljunama Of course! I hope this helps!
1973
A tip for Super Mario 64: Selecting any of the stars numbered 3 to 6 in Jolly Roger Bay results in Unagi the Eel swimming freely in the water, able to hurt Mario. It is possible to always make the eel remain in his hole by selecting star number 2 when entering the level.
1974
Album cover for the unlockable "Introducing Wario Deluxe" record in WarioWare Gold.
1975
In Super Mario World, the face on Lakitu's cloud is coded to always be drawn on top of Mario, even when he is outside the cloud. This can be seen by pausing the game when Lakitu flies just above Mario.
Additional obscure Mario content for suppermariobroth.com.
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