Dream Mary (also called Fancy Mario) is a “special” version of the 1985 NES/Famicom classic game Super Mario Bros. It can be commonly found on pirate Famicom multicarts as Fancy Mario, and rarely on single game cartridges as Dream Mary. It has a bizarre scrolling effect in which the screen splits in half: the right half is unchanged but the left half of the screen displays what’s way ahead of you, on the next screen.
This gives for an interesting and bizarre gameplay experience. Every element that appears on the left half of the screen isn’t solid – you can fall down into ghost pits, seemingly stand up in midair, inside pipes or knock on invisible blocks.
It’s kind of hard to visualize it without seeing it in action. Check out the following YouTube playthrough of the first level of Dream Mary:
Dream Mary is quite a unique experience and as such is often sought among Famicom collectors. But what is Dream Mary anyway? It’s not a ROM hack, it’s way simpler than that. Dream Mary is nothing more than the stock version of SMB with incorrect mirroring.
Tile mirroring is one of the many aspects of the NES architecture. In simple terms it’s the way in which “pages” of graphics memory are arranged for the purposes of screen scrolling. Games can either use Horizontal or Vertical Mirroring, depending on what kind of scrolling they need to do. The type of mirroring is selected and controlled electrically by the cartridge by interconnecting certain pins together. Simple games usually have their mirroring setting hard-wired, while advanced games such as SMB3 can switch the mirroring on the fly through its mapper chip.
Super Mario Bros. uses Horizontal Mirroring, it expects the video memory to be arranged in a specific way for correct horizontal scrolling. If you were to set Vertical Mirroring on a SMB cartridge, the memory organization changes, scrolling data is interpreted incorrectly, and the result is Dream Mary.
If you want to know more about Tile Mirroring, check out this excellent resource: Mirroring – Nesdev Wiki
Dream Mary is nothing more than SMB with Vertical Mirroring
That’s all the magic of Dream Mary. As you probably have guessed by now, a regular SMB cart could be converted to Dream Mary just by switching its mirroring. Old Nintendo cartridge boards (like those used for SMB) come with conveniently placed and clearly labeled solder pads for selecting the appropriate mirroring for the game contained in the ROM chips, this makes the SMB->Dream Mary conversion process extremely straightforward.
I’m going to show you how to convert a common Super Mario Bros./Duck Hunt NES cartridge intro Dream Mary/Duck Hunt in two easy steps.
You will need:
- Super Mario Bros. / Duck Hunt NES cartridge
- Gamebit screwdriver (to open up the cart)
- Soldering Iron
- 60/40 Rosin Core Solder
- X-Acto Knife
Using the gamebit screwdriver, take apart your SMB/DH cartridge. Remove the printed circuit board from the plastic casing and set it on a table with the chips facing you:
It’s a good idea to clean the contacts at this moment. Now, see those little circles marked H and V?
Yes, those are the pads that select what mirroring to use depending on which set of pads is connected together. The H pads are bridged together by a thin strip of copper which can be clearly seen in the picture. To turn this SMB cart into Dream Mary, you need to break the connection that bridges the H pad together and connect the two segments of the V pad together. You’ll use your X-Acto knife to cut the fine copper strip on the H pad and the soldering iron to place a blob of solder between the V pads. Couldn’t be simpler!
Take the X-Acto knife and cut the thin copper stripe on the H pad. Now take your soldering iron and place a blob of fresh solder on both of the V pads. Touch both of them momentarily with the tip of the iron so that the solder melts and bridges the pads together, and that’s it! It should look like this:
Now put the cartridge back together and test it on your NES console. Congratulations! You have turned a common as dirt game into a bizarre experience! Now print out a crazy label for your “new” NES game.
If you ever want to return your Dream Mary cartridge into its original state, just remove the solder from the V pads and place a similar blob of solder between the H pads.
This should work exactly the same with the single cart version of SMB. I haven’t opened up my copy, but you should be able to find the same solder pads in there, and the same procedure applies.
You could also try this on other NES cartridges and see what kind of bizarre effects it causes on the gameplay. Old 1st generation games are the best candidates for this. Complex games might not have manual mirroring select at all.