Expert: Chamale - 5/21/2008

Question
Do you know why the MissingNo and Glitch City happens and if it can be done in
their remakes

Answer
To answer your last question, you can't do these bugs in any of the games after green, red, blue, and yellow. In fact, the Missingno trick doesn't even work in Yellow. The reasons behind these glitches are complex, and not related to each other, so I'll explain them one at a time. The explanation for Missingno is quite long, so it has a summary at the end.

Missingno: The area just to the right of Cinnabar Island is unusual, because it was programmed wrong. In any area where you can catch pokemon, the game is supposed to determine which pokemon can be caught there. Remember that Pokemon is just a computer program, which must store all the data somewhere. There is a certain area in the game's memory which determines which pokemon can be caught in a certain area. This information is reset when you enter a new area. However, the programmers forgot to set which pokemon can be caught just to the right of Cinnabar, so it uses the pokemon from the last area you were in. This lets you catch, for example, pokemon from the Safari Zone to the right of Cinnabar.

However, the Missigno bug goes further than that. When the old man shows you how to catch Weedle, the game changes your name to "OLD MAN". However, the data for your name must be stored in a back-up location so the game remembers it. So, it stores it in the data for which pokemon can be caught. This seemed logical to the programmers, as this data would be reset once you entered a new area. However, this data is not reset when entering the water just to the right of Cinnabar. So, the data from your name affects the pokemon that can be caught. Here's how it works:
Missigno will appear sometimes, regardless of name.
The first letter of the name has no impact.
The second, fourth, and sixth letters affect the level of the first, second, and third pokemon.
The third, fifth, and seventh letters will generate a certain pokemon, depending on what they are. For a complete list, see
http://tasvideos.org/PokemonTricks/Values.html

My favourite name when starting a new game is A?D?w?x, which gives you level 230 Mewtwo, Missigno skeleton and a different Missigno skeleton.

Missingno gives you 128 more of an item because it changes one digit in the gameboy's binary data system. In binary, 1 means 1, 10 means 2, 11 means 3, 100 means 4, and so on. By changing the 8th digit by 1 (eg from 00000101, meaning 5, to 10000101, meaning 133), it increases it by 128. The reason the symbol is glitchy is that the game tries to represent 12 or 13 with a single digit, but it doesn't know how, leading to something odd. This is also why Missingno looks strange - the game tries to load data that doesn't exist.


SUMMARY: The Missigno glitch works because the area to the right of Cinnabar was badly programmed, so talking to the old man can confuse the game. The aberrant pokemon you will see depend on your name, and I've added a link to a list of what letters bring what pokemon.



Glitch city works because when you save and reset, the game becomes confused as to whether or not you are in the safari zone, so it lets you leave. However, it is still counting down 500 steps. When those steps are over, the game knows to send you to the Safari Zone building. When you leave, it knows that you just left building #4 (according to the programmers) of that area, which works well in Fuchsia city. However, in another city, you'll come out of an unusual building. But the glitch occurs when you're in an area with less than 4 buildings, meaning you come out nowhere. The game gets confused about where you are, tries to read data that doesn't exist, and gets scrambled up. Interestingly, glitch city looks the same every time you do it in a specific area. One of my favourites is Cycling Road's glitch city, where your character tries to walk downhill unless you stop him.

An interesting effect is tied to Glitch City: If, on your 500th step, you are in mid-air over a ledge on a bike, you will be able to walk through anything while in the Safari Zone building. Saving or leaving kills the effect, but if your last pokemon faints from poisoning while in the building, you'll walk around freely in the outside world. Be sure to have something with Fly, in case you accidentally trap yourself.


I know of a couple other glitches, like one which lets you catch any pokemon (even Mew!) without a gameshark, and another that lets you skip the first and last gyms. If you'd like to hear about the other bugs, feel free to ask.

One more thing, there's a very interesting video of a computer winning Pokemon Blue in just under 1 hour, 20 minutes, using a variety of bugs. Link:
http://video.google.ca/videoplay?docid=6966379624591852795&q=Pokemon+blue+TAS&ei...