Pac-Man Kill Screen Explained

Coincidence or not, saying 256 at 2:56 is pretty amazing

Wow. You're the first person to actually explain HOW it happens. Everybody else just said "256 wraps around to 0", and that's it

3:50 That falling 1 is so sad. :(

Oh, the havoc a simple integer overflow can cause. It never stops being entertaining.

Interesting fact: Namco Classics for the Nintendo DS has an option in the settings to fix the 256 level bug, allowing the game to continue :)

For anyone left wondering why the tiles are drawn in such a weird order, I'll have a go at explaining. I think it's a really clever solution, but some might find it boring, so... As Pac-Man is an 8-bit machine, it is only capable of counting up to 255, but the display resolution is 224×288. In order to get pixels beyond 255 for the height, some are taken from the sides and put at the top and bottom of the screen. In practice this means that the tile map in memory is 32×32 tiles, where each tile is 8×8 pixels, but the tile map is displayed as 28×36 on the screen. The maze is still 32×32 tiles, but columns 0 and 1, and 30 and 31 are not visible. This is the reason the characters disappear when the go through the tunnels. The reason the main part of the screen is drawn top to bottom and right to left is that the whole screen is rotated 90 degrees to be in portrait aspect ratio. The cabinets just used standard 4:3 CRT screens turned on their sides.

The reason this bug exists at all is due to the programmer not thinking anyone would ever max out the machine and reaching the 256th level. And because of that, he never tested his 8-bit code for that contingency. At least now people can burn a fixed eprom for this problem if they so choose.

Fascinating. Extremely well done video!

though, imagine being the first guy to reach 256 "Hey, what happened to my game???"

"now let's get into the more technical stuff" But I haven't understood anything said so far.

This is actually a lot easier to understand than I had expected.

I love how people think glitches as something that’s wrong with the game, but that far from the truth. The game continues to try and do its job even when one thing is out of place, making an almost always entertaining mess. Great video as always mate, look forward to the next one.

Dig-Dug has a kill screen which also happens at Level 256! The level layouts vary in Dig-Dug, however, so "Level 0" loads garbage level data, placing an enemy right on top of the player.

There is an endless version of Pac-Man Called ‘Pac-Man 256’. It’s an app where you are in an endless Pac-Man with a scrolling screen being chased by glitches. I always wonder why the number 256. It all makes sense now...

Can I just say, aside from being really interesting and well-articulated, your videos are very aesthetically pleasing. The way everything is laid out and animated is just on point. You need to be in web/app design or gaming or something lol

Probably one of the scariest, most influential computational bugs of all time. Today this kind of glitches are treated as "The system doesn't know what to do so it just throws in random shit and colors", but this is so painfully logical that I don't even know how to feel, it makes too much sense and I literally can't think what would've happened if it were any other way. Fascinating.

A great explanation of the Pac-Man Kill screen! I never knew what was going on, but now it makes a whole load of sense! Thanks for making another great video!

Excellent video. Like that you put in the work to reverse engineer the exact output of level 256 instead of just leaving it at "register overflow"

I've known the specifics of this glitch for years now, but never seen a video on the specifics. Really nice to see one, finally. Hoping to see some for games like Galaga and Dig Dug in the future. :)

Loved this!