The Official 2600 Easter Egg and Programming Mysteries Thread

[Skylark68]

This may be common knowledge, but why does Maze Craze have the flashing lights/colors before each stage? It totally trips me out.

[Chris++]

The maze starts out as a simple grid of uniform squares; the new routes are being drawn randomly between them while the screen flashes. Why the maze-forming process is being hidden is anyone's guess. Maybe it's completed more quickly than it would be if the screen were accurately refreshed during each cycle.

[Nukey Shay]

Like other early "complex" games, the display kernel is skipped altogether during the routine. Although this does speed up the process at least twice as much to run the routine in question, a more-important advantage is that the program does not need to use any temporary ram memory storage to draw the display...so that can be utilized here instead. This also makes the display less-confusing to a player...some games may be altering other display variables as it "thinks" (Video Chess), or make the game more of a challenge (Maze Craze's paths are done in reverse - which would reveal the correct path as someone watches it being generated).

 

 

The color-shift deal was put there only because it doesn't "cost" anything to do it...just update COLUBK with whatever value happens to be sitting in a register once in a pass or so (and serve as a visual reminder that the game has not crashed...I guess).

[Chris++]

Ah...nifty! That's good to know. I've wondered about the specific reason for that for nearly twenty years. (But not...y'know...the whole time.)

[Syntaxerror999]

Heres a small easter egg for adventure... Sort of.

 

On the game select screen, if you hold down/right on the joystick, the player will appear and you can move around the screen. There is not much more you can do.

 

Also, if you try to go through the fake passage in the hidden message room and hold up/right you can get to the other side of the message.

[Kittenmommy]

Heres a small easter egg for adventure... Sort of.

 

On the game select screen, if you hold down/right on the joystick, the player will appear and you can move around the screen. There is not much more you can do.

 

Also, if you try to go through the fake passage in the hidden message room and hold up/right you can get to the other side of the message.

 

If you take the bridge with you into the secret room, you can use it to go right through the fake passage and into the blue maze!

[gilbahat]

Here's my stuff for solaris:

 

1. Looking in the manual, it says "cobra ships are sent to persuade you to vacate a cluster". well, if you block a combat group's path from moving and then go back to the combat view, voila - cobra ships appear out of nowhere. this can unfortunately happen during another unrelated fight, with devastating results.

 

2. if you do that while on a planet, you will get invaders instead of cobra ships. if you plan well enough, this can happen inside a corridor. fun.

 

3. quadrants are ranked by difficulty - you know the quadrant's difficulty by the amount of gates on a corridor or cadets on a zylon planet. it's not linear, too - some maps far along in the game have a difficulty rating of 2. case in point is when you try #1 on the first map - you will get cobra ships that can't shoot at you.

 

4. you can tunnel through enemies in 2 different methods:

* if you move exactly when they move, you may be able to pass through.

* if you attack a combat group, then locate yourself on another combat group (but not engage it!), then win the fight - you can pass through the other, unrelated group. if it was a map edge, you'd even get to the next map. you can see it here in action:

 

http://www.youtube.com/watch?v=8JLdalkHLW0

 

5. there's a tiny time gap between being winning an extra life and the zylon planet being destroyed. if you abort fast enough, you can re-engage the planet and get more lives this way.

 

6. for reasons not entirely clear yet, sometimes combat groups will move a lot more than once. perhaps this is a discrepency between moves happening while on the combat view and on the quadrant view.

 

7. even when your rader is broken, it is fully functional, as you can see the distance to the target and whether it's left/right to you by the indicator, so nothing is lost.

Edited May 28, 2012 by gilbahat

[gilbahat]

[Chris++]

Regarding Adventure:This might never be answered, but I've always wondered why the useless second exit from the Red Dungeon is provided (inside the White Castle) -- or if Robinett ever mentioned its original purpose.

[Nukey Shay]

Just that it is a mistake.

The passage was originally intended to lead to the upper part of the white castle - i.e. the "balcony".

 

W.R. decided not to use this idea, but the wall gfx were not corrected.

 

"One of these exits is the normal one through the door of the castle, but the other exit, from the hard-to-get-to room in Section 2, leads to the "balcony" of the White Castle. The link from the Red Maze to the balcony is one-way, however; it is not possible to go back into the Red Maze from the balcony. This violates my principle of making all paths retracable, and was a mistake--an earlier idea that was rejected but never expunged".

Edited July 14, 2012 by Nukey Shay

[Chris++]

WOW -- I've never seen that essay! I'm glad I asked, for that alone -- thanks for the link. Which book is that from?

[Kittenmommy]

What's not so well-known is that the dot does not need to be present...it just needs to be moved out of it's starting screen. You can use the bridge in the catacombs below the entrance to get behind the panel and enter the signature room.

 

Wait... what?

[Kittenmommy]

Heres a small easter egg for adventure... Sort of.

 

On the game select screen, if you hold down/right on the joystick, the player will appear and you can move around the screen. There is not much more you can do.

 

Also, if you try to go through the fake passage in the hidden message room and hold up/right you can get to the other side of the message.

 

Not much you can do there, though. And if a dragon shows up and sees you there, he'll eat you up!

 

You can also take the bridge into the hidden message room and position it in either the top or bottom (I can't remember which and neither my Atari nor my Atari Flashback are hooked up at the moment) and go through, and you'll appear in the Blue Maze. I... don't even know how that could be. Heh.

[Nukey Shay]

That's where the map sends you when exiting North or South.

LFF29: .word BelowYellowCastle ;playfield bitmap shared from that screen
LFF2B: .byte $66 ;purple (color setting)
LFF2C: .byte $0A ;light grey (B&W setting)
LFF2D: .byte $21 ;8-clock ball, reflected playfield w/sprite priority
LFF2E: .byte $06 ;North=BlueMazeBottom screen (large open area)
LFF2F: .byte $01 ;East=BelowYellowCastle screen (i.e. South of the blue maze)
LFF30: .byte $06 ;South=BlueMazeBottom screen (large open area)
LFF31: .byte $03 ;West=LeftOfName screen (the panel screen)

 

The reason you can't go North through it's own exit is because the lower wall in the BlueMazeBottom screen will block you. The ball sprite will be flickering at the top due to the playfield collision. Putting the bridge on the "Name" screen's lower wall allows you to pass safely into the N/S corridors of the BlueMazeBottom screen if you are lined up with one.

 

Regarding the dot, there is additional code when moving East to a connecting screen. This checks if you are NOT moving from the "LeftOfName" screen...and is the dot at it's original screen. If either are true, the screen number is fetched from the map. Otherwise,

your screen number is changed to be the "Name" screen.

;Check and Deal with Right
DealWithRight:
LDA $01,X           ;Get the object's X coordinate
CPX #$8A            ;moving the player sprite (ball)?
BNE DealWithRight_2 ; Branch if not
CMP #$9F            ;Has the object reached the right
BCC MovementReturn  ; Branch if not
LDA $00,X           ;Get the player's room
CMP #$03            ;Is it the LeftOfName screen?
BNE DealWithRight_3 ; Branch if not
LDA $A1             ;Check the dot's screen number
CMP #$15            ;Is it in it's starting screen?
BEQ DealWithRight_3 ; Branch if it is
;otherwise, Manually change to secret room...
LDA #$1E            ;Set value to the "Name" screen number
STA $00,X           ;And make it current
LDA #$03            ;Reset player's horizontal coordinate...
STA $01,X           ;to the left side of the screen
JMP MovementReturn  ;Exit

 

The part which stands in your way is the panel collisions. Panels are drawn using the missile sprites. When the program is first starting...Missile0 is set to the left side, and missile1 to the right. "Frying" the console has the effect of starting at a random spot in the program, so this positioning code is not executed - the missile panels will not be at there proper locations.

 

But anyway...

 LDA CXM1FB          ;load missile1/playfield collisions
AND #$40            ;check ball-missile01 collision only
BEQ BallMovement_2  ;Branch if no collision
LDA $96             ;check object2 (to print)
CMP #$87            ;is it the dot?
BNE PlayerCollision ;allow collision if not
BallMovement_2:

 

On each display frame, 2 objects are queued for printing. Note that the dot *must* be cached as the second object on the collision frame, or the panel will be allowed to block you (this is why the dot doesn't always work).

 

Apart from frying the console, the only other way to move around the panels is to use the bridge from a connecting screen. The part I mentioned is to drop the bridge as high as you can (without it disappearing) on the right side of the first catacomb screen. Line yourself up with a bridge side so that you can grab hold of it once you are stuck in the wall from going through the bridge. Then continue to move slowly though the wall...angling the stick to drop the bridge so that it's side is always right next to you as you force your way though the playfield.

 

An easier way is to use the magnet and the bridge:

In the BlueMazeBottom screen, carry the magnet to your upper-right with the bridge present. Move carefully so you don't accidentally hit the bridge. By moving South, you automatically walk through the bridge's sides. It will follow you down the screen being attracted by the magnet...and also "warp" to the next screen when it gets too low to be displayed. You can freely move South anywhere you want by doing so. LeftOfName is directly South from BlueMazeBottom.

 

If the dot is anywhere BUT it's starting screen when you move to the right from the LeftOfName screen, the code will place you in the "Name" screen.

[Nukey Shay]

Correction:

Carry the magnet to your upper-left.

[Nukey Shay]

Which book is that from?

Inventing The Adventure Game. The publisher he sold it to folded...so it never got made.

The full non-PDF script is at his own site:

http://www.warrenrobinett.com/inventing_adventure/

[Chris++]

Thanks for the link!

[keithbk]

In case anyone was interested, I did a video that compares the Easter Egg in Adventure with the one I put in Another Adventure. Please note that the video also discusses other gameplay issues as well.

 

[rgr1973]

Yars' Revenge: Hit a swirl in mid-air with the cannon. Then find the “Ghost of YAR” (a black, vertical line that appears behind the explosion graphics) and position yourself on the lower third of it. If done right, when the explosion ends, the game will stop and the letters “HSWWSH” (for Howard Scott Warshaw) will appear. {Steve Haubner or Michael Finnin?}

 

**********************

 

 

The things you learn when you're suffering insomnia at 4AM!!!! I always thought I had a defective cartridge, but now I find out I don't!

[Foxsolo2000]

Been flicking through some old gaming mags (1982/83) and rediscovered some old (suppossed) easter eggs in certain games. At the time (and to this date) these eggs were never proved so I am wondering if anyone ever heard of them or discovered why they were in the game.

 

Raiders of the Lost Ark - Most of my questions were answered by Nukey in another thread but one question always remained was when Indy walked up and down the side of the Mesa Field a mysterious dot can be seen in the Mesa Field and can be controlled to a certain extent i.e on one occassion I actually managed to make it move down the screen and disappear off the bottom of the screen. Was there any purpose to this dot?

 

Night Driver - Back in 83 some guy claimed he had found the designers initials in the game but he never said how he found it. Are the initials in the game?

 

ET - In 1984 a gamer actually posted a pic of a bizarre scene he had found in one of the pits. It was the scene from Close Encounters of the landing site from the film. Again no explanation was offered as to how it was found save that the player fell into a pit and there it was.

 

Defender - In 1983 another gamer (with no proof) claimed that he had been playing the game and had dived into the city to suddenly discover a room he had never seen in which a green wall blocked his way. He blasted through the wall to find himself in a room with the initials BPPB slap bang in the middle of the room. Can this be proved?

 

Dodge Em - Is it possible to make the 2nd crash car on game 3 to make a sudden right turn and disappear?

 

Any input would be appreciated

[Nukey Shay]

Raiders: Walking on the border of the mesa field is a glitch. The dot is the grappling hook being positioned incorrectly if you do it.

 

Night Driver: Very doubtful, as Rob Fulop programmed the game (the initials RF do not resemble score digits or any of the 4 displayable game objects - tree, house, pedestrian, or car). The kernel does not display anything other than those images.

 

ET: There's a number of objects that appear in the pits. None of them particularly resemble the landing site in CE3K, tho (and the game does not display as complex images your description suggests).

 

Defender: Bob Polaro (BP) programmed the game and the actual Easter Egg is to carry a human to the 25th scanline on the 25th wave to transform all enemies to those initials. As before, the display kernel is not designed to display things you describe (room, destroyable wall).

 

Dodge 'Em: Shouldn't happen in regular gameplay AFAIK...a frying glitch?

[Foxsolo2000]

Thank you Nukey for the input, that satisfies a number of questions and put to rest several urban legends. One question though. Was paint shop around in 1984? I ask for the pic of the landing site sent in by a reader did indeed look like the one from the film and was most probably faked

[apemaster]

E.T.: (1) Collect all the phone pieces and give Elliot 7 pieces of candy. Then, revive the flower. It will change into a YAR and fly away. Repeat this for the next round and the flower will change into Indy. Repeat this a 3rd time and the initials “HSW3” (for Howard Scott Warshaw – the 3 denotes this is his 3rd game) will appear! {Howard Scott Warshaw}. Actually you don’t have to get all of the phone pieces for the trick to work. You only need to collect the “H” piece for the YAR, the “S” for Indy, and the “W” for the initials.

 

(2) The initials of the graphic artist, Jerome M. Domurat, are hidden in the game as well. On game #1, give Elliot 1 candy. Then, whenever you both are on the 8-pit screen, the letters “JD” will appear on the top status bar. {Ronnie Dingman and Thomas Jentzsch}

 

OMG, if they'd used the time to include these secrets for making the game better instead, maybe Atari would've still been alive today!

[+Cafeman]

Does Enduro have any secrets? Or a point where you see something like "!!!"?

[Nukey Shay]

Nope. Just the trophy.