Pac-Man Kill Screen Explained 

I agree. The 255+1=0 thing alone doesn't explain the messed up stuff on the right side, but this video does.

It isn't so simple to understand that it relates to the level counter.

It's Y2K literally. Wraps to zero and everything goes haywire

@@cubah1 Except it happened

@@neilisbored2177 Y2K did happen. But every programmer and company saw it coming from miles away and braced themselves to handle it gracefully.

Devon Hayden He does not, unfortunately.

It seems like he said hundred fifty six, but ehh he says 256 so you're right

@Ersanio That was a coincidence, like back in the day, we'd watch TV with the volume off and the stereo wide open and hear things that matched the TV screen. Sometimes it made more sense! Lol.:-)

@@icenesiswayons9962 you sound like a boomer

@@mackback319... you sound like a sooner

An option?? You would expect them to just fix it without asking.

They did fix it without asking, but it is in the options menu of the game you can fix the level 256 glitch or leave it as is if you want to witness the glitch for yourself.

AtKiba Canal i don't remember when the last time you played pac man but surely you remember level 256 is no easy feat

If they do something of their own volition like that, then why would they?

actually they did but only skilled pac-man players can get to level 256 with the fix on.

don't worry, the carry flag will catch him

*R.I.P 1*

F

the love on the animations are so cute :O

This is so sad Can we hit 2 likes

nin10doadict you might want to check out stryder7x for more glitches. He only does Paper Mario though, so you might not be interested.

and an integer underflow in that game can cause a softlock in every room with enemies

In other words, playing Pac-Man crashes Paper Mario.

Actually I've been subbed to stryder7x for quite a while now. :D

Link8304 - Gaming in Hyrule Is this a meme?

That is actually really interesting!

You deserve a like, my friend.

Huh, and I thought the game writes the graphics from top to bottom and from right to left because it's japanese.

That actually makes sense!

Then, what is with the classics made in 2016? Bandi Namco created just "PAC-MAN" for the mobile version allowing a classic mode, through all the advancements for 38 years caused better and advanced stuff, having an advantage of removing a problem of a kill screen caused long before at 1980. So really, it can be hard to do in the mobile version, so right now, the kill screen is possible to fix. Saying goodbye to the level 256 38 years ago.

There's a fix for Ms. Pac-Man's (rather more involved) kill screen as well. Gotta be impressed when people find a way to shove a bugfix into the tiny bit of rom used by a 35 year old game.

In this case wouldn't it just be a reordering? At the start of the level, draw the fruits, then the maze. Then leave them (as I assume the maze is being done already for the dots' sake) until the next new level.

Probably somebody did realized this back then, but the team said "Nahh, they wont get past level 255" and so it wasn't worth fixing it

Asterra2 Is there a video explaining Ms Pac Man's?

It was originally designed for arcade cabinets right? They probably thought no one would ever stand there for ~3 hours doing it, not getting bored, and not loosing once...

It would be scary

I'd be to scared to play the level

Bill Bastable would've felt relieved.

@HitWalkHook I think that the first person to get there actually sent a picture of it to the devs.

That would be Billy Mitchel. First man ever to beat Pac-Man and get a perfect score

Lol

Heh heh. Know what you mean. That said, just using my brain for a general understanding of the matter, it essentially has to to do with the limitations of the coding based on the data available to write coding that basically equates to “if x then y”. 255 being the maximum number, once you hit 256, those “if x then y” formulas start to make no sense. Or another way to look at it, the algorithmic coding of the day allowed for 255 levels of fun gameplay, which was more than enough for 99.99999% of the arcade visiting public. Which was more than enough to compensate for the fuckery that starts when you roll over to Level 256 (aka Level 0).

I have.

DenkyMan then does that mean that you did not understand “seven”?

Frr

are you gonna speedrun Pacman?!?

its basically crossy road

@@lisacamarillo8744 but PACMAN. 256 pacman. Even the teaser says it's inspired by the 256th level. Unless you knew that.

@@lisacamarillo8744 So basically Frogger

if pac man 256 level kill screen land move dot are lower

@@thisissaah_3536 *Pac-Man

Yep this is a good example of computers doing *exactly* what they're told to do, even if it doesn't make any sense

1980s error handling: "what error?"

Yep, it's perfectly possible to add a special exception to prevent the level counter byte from ever being 255, but it's not worth wasting those extra bytes when your ROM space is limited.

VuurniacSquarewave well in the later Pac-Man machines, they introduced a bored which if someone did get to level 255+ an integer overflow would occur. Just like donkey kong, nibbler and countless other games.

If only computers nowadays handled errors and giltches like this instead of protecting memory and throwing an error message up then quitting.

Liar

@@imissjokesonpurpose no u

@@torin1006 uno reverse card

@@imissjokesonpurpose You've activated my trap card! Your reverse card got sent to the shadow realm.

@@torin1006 *ye well ur mom got sent to the shadow realm becuz of me*

Same happens with mario vs donkey kong arcade lvl 22

There's also a kill screen in Galaga, but it's effects can vary depending on the difficulty setting (some machines will load a normal level, while in others the game will crash).

+Another Anime lover Unlike Dig-Dug or Pac-Man, however, Donkey Kong does not have a glitched screen at level 22. Rather, it has a glitched timer that doesn't even give you enough time to get past the 2nd girder. It's another integer overflow. The timer is calculated by taking the level number times 10, plus 40. There is a check at the end of the code to prevent the timer from exceeding 80. If the level number is stored in B, and the timer is in A, then this would be the equivalent code in BASIC (I'm translating to BASIC for anyone reading this who isn't familiar with Z80 programming) A=B : REM Set the Accumulator to the level number A=A*2 : REM The Accumulator is now twice the level number A=A*2 : REM ... and now it's four times the level number A=A*2 : REM ... eight times the level number A=A+B : REM ... nine times the level number A=A+B : REM ... ten times the level number A=A+40 : REM and now A=B*10+40 as intended IF A>80 THEN A=80 Note that the *only* error checking is done *after* the math. The problem is that A is an 8-bit number, so it can only hold a value between 0 and 255. So what happens when you hit level 22? (22*10)+40=260, so A wraps around to (260-256)=4. Since 4 is less than 80, the error checking doesn't catch the problem, and you start level 22 with a timer of 400. The unusual thing here is that the game checks the level to make sure that if you ever get past level 100, it forces it back down to level 99. So they *did* anticipate that players could make it to level 100, but somehow they overlooked the timer bug, and you can't get past level 22 without patching the ROM. What was *supposed* to happen is that if you are on level 4 or higher, the timer will always start at 8000 (which is the reason for the IF A>80 THEN A=80 at the end). The patch is simple and fits in the existing space. You just add an error check before the math, and remove the IF statement at the end. A=B IF A>=4 THEN A=4 (everything else is the same, but remove the IF A>80 at the end)

@@SpearM3064 not sure if you're really smart, or just a huge geek, lol

FairPlay137 minecraft limits at 256 too

I did this while recording the gameplay footage--you go back to level 1 (just a cherry), but the enemy difficulty still behaves as if you were on level 257 (fast ghosts and they don't turn blue when you eat a power pellet).

Thank you! That's kind of what I suspected would happen (since the only variable causing an issue here is the level icon) but it's wonderful to have it confirmed. I wonder if a ROM hack could be made that adjusted for this, or if one already exists...

Interesting, but why do the ghosts stay at faster speeds? I assume a second variable has to be responsible for that if it isn't the level number variable.

Chris Waegelein

What? The ghost speed variable is 16-bit???

if only Nintendo did the same...

Ironic, as it's a video about the game being imperfectly executed

Galaga and Dig Dug? You wouldn't happen to have read Don Hodges' old website posts about this stuff, would you?

Yep.

Everything computers do is ordered. It's just that some happen to ruin the intended function. (Technically, everything everything does is ordered, thanks to the laws of physics.)

It's still a glitch, an unintended consequence of an oversight is still unintended.

I think that by order the OP meant “in order”, not “giving an order”

I use After Effects for pretty much all of the animations.

Retro Game Mechanics Explained you sound familiar...

I'd love to see that.

I wonder what his fans are called?

**turns around**

@@smashfanx7560 r/madlads

@Spirit Creeper 40 Thanks!

Hopefully he used a script... Hopefully

I think I recall reading he uses scripts in After Effects to show technical things within the videos.

9:44 draws a pac-ler

And bounds checking

My 9th-key pattern had me go through the PacMen to impress chicks.

13th key, Pac slows way down to "start level speed", while the ghosts are all faster than Pac (not just Blinky). Tough. I think the furthest I've ever made it is 15th key...apparently I'll never see the "kill screen".

Acoha This is guy is fantastic! Have you ever heard of RetroAhoy? His videos are great too c:

Me & my dad call them sundaes, and we thought the bell was a gold nugget lol

Mezgrman Aw, you should have told us what you thought. I'm interested.

Glad u like it, I did

Yeah that was exactly my thought. "It's because reaching level 256 rolls over the counter and screws things up, right?" Yes, that is in fact what happens, but it doesn't tell anywhere close to the full story.

WHAT WHERE YOU THINKING A YEAR LATER!?!???

Nah, A+++

No its A+++++++++++++... +

Actually, it's very easy to do this: just don't add a crash handler. Problem is, then you can have bad shit happen on modern PCs and stuff.

tbh I wouldn't like that very much, I always found kill screens startling, I don't like seeing games suddenly spazz out in weird and unexpected ways, it hurts my eyes and gives me the fright of my life

Elven Insanity The modern equivalent are engine bugs/flaws. Want a modern example? In Call of Duty 4:Modern Warfare, if your computer runs the game fast enough (Either 125, 250, or 333 frames per second), the game calculates physics wrong, letting you jump higher, reload, and move faster. Another is a more classic example. In Quake 1, running and jumping on slopes surfaces influence your momentum, meaning that high enough ramps you can run up and jump from will send you very high

a lot of source games like portal or half life have backwards jump speed glitches, similar to the BJLs in super Mario 64

Another framerate-related problem: If you hack Super Mario Sunshine to run at 120FPS, you can't enter level portals! There's also the all-too-common state machine glitches and animation engine and physics errors in modern games. And SM64's parallel universes

With adding 1: actual 0 -> shown 1 actual 1 -> shown 2 ... actual 254 -> shown 255 actual 255 -> shown 0 Without adding 1: actual 0 actual 1 ... actual 254 actual 255 actual 0 (back where we started) ... They chose the former one, because they didn't think about overflow and they wanted to start with 1.

This is why we die faster at larger age numbers, the world is trying to stop us from getting to age 256 and glitch out half the universe

R.I.P Japan, Created Nintendo And Was 256 Years Old

Thank you, I'll consider it for future videos!

If you do that, I wonder what happens when you reach level 257…

@@NoriMori1992 You probably go back to level 1

@@NoriMori1992 You just go back to Level 1, but the game is still at its maximum difficulty. (You don't even need to cheat to prove this - use the "rack advance" feature either in MAME or an actual arcade machine to see it.)

*0th

There's zero likes, you are too early

MarioFanGamer r/woosh

Suwin Khamchaiwong r/woosh x2

even better, this comment has 64 likes at the time of me viewing it

CHAKA24 I played it

'Course you do.

I wish I had $FFFF

@@RodBeauvex When you're so broke that you cause an interger overflow in your bank account!

Wouldn't you being poor cause an integer *under* flow?

@@RodBeauvex $6666 is what you meant? F=6

I am the fool, they have the proof.

For now perhaps, but the world is constantly making better fools.

I find it interesting that the simple 8 bit stuff sucked up.WAY WAY more hours than way more advanced games that came later. At least for me...

Wow, I just realized you're right. Wow. That's truly amazing right there---

Damn you

or 1/2 of a sandwich