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Proto:Dr. Mario (NES)/PlayChoice-10 Prototype

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This is a sub-page of Proto:Dr. Mario (NES).

Download.png Download Virus (PlayChoice-10 Prototype)
File: Virus_(Dr._Mario)_(USA)_(Proto).nes (64 KB) (info)

The PlayChoice-10 prototype of Virus was found installed in an otherwise-unremarkable PlayChoice-10 arcade cabinet in 2012, which was likely used to playtest new NES games at a Chuck E. Cheese's restaurant at one point.

This build is much like the prototype of Super Mario Bros. 2, in that it shows the game during the transition from its original style to its more familiar one.

To do:
Look for other differences than the ones listed by someone with only a passing knowledge of the game.

Title Screen

Virus 1989 Proto Virus 1990 Proto Virus PC-10 Proto Dr. Mario Final
Boring Still Boring Getting there... Yay for Doc + Blue Virus.

The title screen has begun to take the form of the final, with a new (more "bubbly") logo compared to the first two builds, a checkered background, and the option of 1-Player or 2-Player modes. The logo still has no animation, the menu border doesn't have its distinctive pill shape yet, there are no characters visible, and no music plays. There are also no copyright or trademark symbols, although both are present in the CHR-ROM and the former had been used in the earlier Virus builds.

The background was changed from a sort of ruby color to a more pleasing green, and the squares that make up the checkerboard pattern were shrunk from 16×16 to 8×8. There's still no gameplay demo at this point, though.

Options Screen

Virus 1989 Proto Virus 1990 Proto Virus PC-10 Proto Dr. Mario Final
Blank spaces replaced with dots Now we have music Now we have, er, a different options screen!
  • The menu is now much closer to the final, but still has its own style: though not apparent here, this build uses a flashing pink box for a cursor, flashing every other frame to create a transparency effect. Dr. Mario uses a different cursor for each option, making it easier to see which options have been chosen.
  • The option to keep pills floating in mid-air after clearing viruses or other pills has been removed, possibly because it made the game too hard and/or frustrating.
  • Like the title screen, the squares that make up the checkerboard pattern were shrunk from 16×16 to 8×8.
  • The border in Virus is a simple square, while the final border is shaped like a clipboard to fit the whole "doctor" theme. Nice touches like these are missing at this point in development.
  • The Speed setting is named "Sick Level", with "Easy", "Norm", and "Hard" settings. This was likely renamed to make it clear what this setting actually does.
  • The Music choices just use letters, not unlike Tetris, and the blank option turns the music off. The final renames the setting "Music Type" and the choices to fit the "doctor" theme: "Fever", "Chill", and "Off".
  • Trying to go past the last item on each option setting will go back to the first option, a wraparound feature that was strangely removed from the final.

1-Player Game

Virus 1989 Proto Virus PC-10 Proto Dr. Mario Final
Bonus offer upcoming Order now and get a bonus 300 absolutely free Bonus offer has expired
  • Unlike the title and menu screens, the in-game background squares were increased in size from 4×4 to 8×8.
  • Compared to the first two builds, things have improved aesthetically: the Megavitamins now have their distinctive outlines, the viruses now take center stage, and both they and Dr. Mario look almost like they should.
  • The hospital aspects, which had previously been more-or-less an integral part of the first two builds, were removed from the game entirely and relegated to the instruction manual upon release.
  • Internally, the playfield is one row taller than in the final: pills that go past the top line of the playfield are preserved but hidden, and drop back into view as soon as pieces below them are cleared. Trying to get rid of pills or viruses with the "hidden" line is not possible until the hidden pills drop back into view. The final simply removes any pills that settle in this area.
  • When generating levels, three viruses of the same color will sometimes be placed next to each other in a row or column. The final does not allow this.
  • Hard difficulty begins at 10 frames per step, which was slowed down to 14 frames per step in the final.
  • Points are no longer given for clearing excess pills. In its place is the "BONUS" counter, which starts at 300 and decreases every time a new pill is placed. Clearing a level awards points for every remaining bonus point, which increases depending on the difficulty setting (10 points per bonus point in Easy, 20 per bonus point in Normal, 30 per bonus point in Hard). For reasons unknown, this element was removed in subsequent builds and all released versions of Dr. Mario.
  • The default high score was increased from 5,000 in Virus to 10,000 in Dr. Mario.
  • The player's score cap was increased from 999,999 in Virus to 9,999,999 in Dr. Mario.
  • The background color is the same regardless of the selected difficulty level. The final version gives each difficulty its own color.
  • The magnifying glass is oval-shaped and missing its handle, suggesting it was originally a Petri dish.
  • The large viruses simply dance in place, and the Blue Virus was moved to the opposite side in the final. They also don't laugh when you lose, although those frames are present in the ROM.
    • The viruses' dancing speed is tied to the current music track by this point, though Fever and Chill seem to have been swapped in the final version. Turning the music off causes the viruses to stand completely still, though whether this is a bug or intentional decision is unknown. The final version has them dance regardless of the music setting.
  • Clearing a virus uses the same sound effect as clearing a stack of pills. This was changed in the final version, but in a half-hearted manner: the regular sound effect plays unless the last tile cleared is a virus.
  • There is no sound effect for when a virus vanishes from the Petri dish after all of its color are cleared.
  • Any pills that are "floating" when the level is cleared no longer drop.


  • Losing in Virus still brings up a "MISS" message box, something removed entirely from Dr. Mario. This was, however, retained in the Game Boy version.
  • The win tune is the same regardless of whether the player picks Fever or Chill. In Dr. Mario, Chill got its own win tune.
Virus 1989 Proto Virus PC-10 Proto Dr. Mario Final
gg next map gg next map remains. Try next what?
  • The stage clear message was also changed, mostly to fix the wonky formatting of this build. The "PUSH START" message was changed to a flashing "START" sprite. The stage clear music is somewhat different as well.
  • There are no intermission cutscenes in Virus, and the cutscene graphics are not even present at this point in development.
  • Upon finishing Level 20, you proceed to Level 21 and can select levels greater than 20 from the menu screen upon losing, although this is pretty clearly the result of an overflow and not intended behavior as the menu isn't designed to handle numbers larger than 20, and going back below 21 doesn't let you go back up again. The final caps it at 20 no matter what.
  • Levels 21-22 place viruses as high as the third row, hence you cannot stack pills on top to clear them; as a result, the level can sometimes be unwinnable. Levels 23-24 place viruses as high as the second row, making it even harder to complete them. Level 25 places viruses in the very first row, pretty much ensuring a Game Over. Levels beyond those, accessed by losing at Level 21 or higher as detailed above, are often extremely glitchy as a result of overflowing the level counter - viruses are placed in nonsensical locations, sometimes even outside the playing field, as well as generating yellow 0s (which are actually singular yellow pills that fall upon placing the first pill). In the final, Levels 21-24 are copies of Level 20, with Level 24 repeating itself if you clear it.
  • Doing a soft reset while the game is paused will mute the music and sounds until the game is paused and unpaused.
  • Getting combinations gives you 100 points each chain virus clear. In the final version, you start with 100 points and double with every chain.

2-Player Game

Virus 1989 Proto Virus 1990 Proto Virus PC-10 Proto Dr. Mario Final
Virus19892PGameplay.png Virus19902PGameplay.png DrMario2PProto.png DrMario2PFinal.png
  • The 2-Player menu uses a different music track than the 1-Player menu.
  • The option to set the number of wins has been removed.
  • The HUD at the top is considerably different and only shows the virus level of each player.
  • The 1P and 2P markers have not been implemented yet.
Virus 1989 Proto Virus PC-10 Proto Dr. Mario Final
Virus19892PGameClear.png DrMario2PClearProto.png DrMario2PClearFinal.png
  • The winning and losing messages appear in message boxes. The final has the losing player's field visited by a nasty Red Virus with a nasty red X.
  • The 2-Player menu music is played after each win. Apparently Nintendo was very fond of this track.
Virus 1989 Proto Virus PC-10 Proto Dr. Mario Final
Virus19892PMatchClear.png DrMario2PGameClearProto.png DrMario2PGameClearFinal.png
  • Mario is still missing from the winner's playfield.
  • Creating a cascade combo where the pill breaks in half, falls, and clears a virus or set of pills will not play the jingles heard in the final.
  • Winning a match plays the music used for intermission cutscenes in the final version, as the final victory theme does not yet exist in this build.

Unused Graphics

These graphics were overwritten with other tiles in later versions.

This pointing finger may have been an idea for a cursor.

Trade, Mark?
A trademark symbol that probably would have been placed next to the Virus logo.

Whose tiles are these? The answer is...my tiles. Your tiles. Tile's tiles. Tile tile tile
Miscellaneous unused characters from the game's font. The crown was used in the 2-Player mode of the first two builds to keep track of how many matches each player has won, but was replaced by a larger graphic from this point onward. The other three tiles were also unused in the first two builds.

In the final, the viruses laugh at the player if they fail to clear the level. At this point, they move for a bit then stop completely, rendering these frames unused.

Unused Music

Two bad, dreary, and unused tracks remain in the ROM, and can be played by changing RAM address $06F5 to the corresponding ID value (or using the provided Game Genie codes). They were removed in later builds and the final.

ID: 03 (Game Genie code KKUSAIEK ZEUITSYY)

ID: 0A (Game Genie code KKUSAIEK PEUIYSYN)

Graphical Differences

Dr. Mario

Virus 1989/1990 Protos Virus PC-10 Proto Dr. Mario Final
Dr. Half-Asleep
He's even looking at his nose
Dr. Narcissus

Look at the schnoz on Mario! The good doctor wasn't quite done with the corrective surgery at this point, but it's closer: he gained a stethoscope, and he has a black outline instead of brown. His eyes are bigger and his quasi-realistic shoes turned brown, but their shape remained until the final when they were swapped for his signature boots.

Virus PC-10 Proto Dr. Mario Final
I am carrying invisible rice bowls
Whatchagonnado, ah?

Mario's swollen head and hands were thankfully fixed, he now faces directly towards the camera, and he was given a mouth. That's always nice to have. His eyebrows were recolored to black in the final game.

Yellow Virus

Virus PC-10 Proto Dr. Mario Final
I don't want that anywhere near me I'd be sad if I was trapped under a magnifying glass

More changes on the nose front: the Yellow Virus' "nose" was replaced with a more expressive mouth. Also, its shoes are no longer the same color as its skin.

Virus PC-10 Proto Dr. Mario Final
Detonation in 10 This is what happens when you try to feed a fever

See what difference a mouth makes? The final sprite is clearly laughing, while the (unused) Virus sprite may or may not be primed to explode.

Virus PC-10 Proto Dr. Mario Final
A peanut enters and exits its mouth every half-second. It's hell Something's wrong here

The actual Yellow Virus tiles were changed as well, though one frame of this older design is used in the final: to create the animated virus tiles, the game switches between two CHR blocks. In this build, these both use the same design; in the final, one of the blocks uses this build's design while the other uses the final design.

As a result, one of the changed frames is never used. Correcting this will result in the following: Aha!

The corrected animation would later show up (with additional shading) in Tetris & Dr. Mario.

Red Virus

Virus PC-10 Proto Dr. Mario Final
My dose is stuffed dowd Wait, can these viruses get colds?

One last nose-related change: the nostrils on the Red Virus' laughing frame were moved up to a more acceptable place, its shoes were squared off, and its tail moved to the other side.

Blue Virus

Virus PC-10 Proto Dr. Mario Final
Picasso's Blue Period Half-deaf no more

The Blue Virus is missing the inner part of its left(/right, since the graphic flips) ear, which was filled in for the final.

Virus PC-10 Proto Dr. Mario Final
This would be painful if viruses had body parts. And the capacity for pain So what if it's bucktoothed? It's amazing that it has teeth at all

The Blue Virus' final laughing frame is more "standing" and less "trying to do a split".


Virus PC-10 Proto Dr. Mario Final
Sure is a clipboard It's still a clipboard

The clipboard became two pixels wider and taller in the final. Like a real clipboard, it's not very interesting.

Audio Differences

The sound effect that plays when gameplay speeds up (after every ten Megavitamins dropped) was completely changed in the final. The first two builds merely used the Tetris level-up sound.

The "stage clear" theme is slightly different and loops continuously, unlike the final version (which also got a unique theme for Chill, as mentioned above).

Fever has an extra percussion beat towards the end of the loop. It's worth noting that the Game Boy, SNES, and Super Smash Bros. Melee versions of the track feature an additional bridge immediately after the final version of the song ends - precisely where this beat is located in this version.

Due to a minor error in the music data, the lead instrument in Chill is louder than it should be at the beginning of the track.

The 2-Player menu screen has its own music, unlike the final which uses the 1-Player menu theme for both. A minor variant of this track was later used in Nintendo World Championships 1990 and Hello Kitty World.

Whereas the final has a somewhat expansive Game Over music sequence, Virus only uses the brief initial sting, although the percussive sound at the start has less "oomph" to it. The Game Boy Dr. Mario uses this shortened tune as well.

(Source: Original TCRF research)