Bug: After the S.S. Anne is gone, go to the guard that says that the ship is gone. After facing him, keep pressing right and then quickly push the START button. Save and reset. If everything's OK, you should continue facing right. Select a Pokémon that knows SURF and use this move. Instead of surfing to the right, you'll surf ON the guard! Press down twice, and you'll enter the S.S. Anne again.Dr. James
Bug: After entering the Cycling Road from the northern gate, go all the way left. You'll see some trees beside the barrier. Then go south, until a point water appears below the trees. If you go up again, you'll see that the trees that were at north have now transformed into water. If you keep going up, and then right so the water is not seen, and then left again, the water has now transformed into trees, again.Dr. James
Bug: Go to the hotel in Celadon City. Enter the building and go all right, then go up so you leave a space between you and the little wall. Then press the A button. The menu of a PC will pop-up, as if an invisible PC were there.
Bug: Go to Pallet Town, and go to the northern exit. Cut the grass there with the CUT HM. Enter Route 1 and return to Pallet Town. You'll see, by the sprite of your character, that you're in an invisible grass.
Bug: Go to the Safari Zone and enter. Return to the entrance and when they ask you if you want to exit answer NO. Return to the Safari Zone and save, then reset. After loading the file, return to the entrance and they'll ask you to enter the Safari Zone, even though you're already there. Answer NO and leave. Fly to Cinnabar Island and surf in the route that's on the right of the island. After a lot of steps, a ding-dong will appear, returning you to the entrance of Safari Zone with no explanation. Exit, and you'll find yourself in a totally glitch city. The only way to get out of this city is to FLY, so take a Pokemon with this move when performing this glitch.
Bug: For this glitch, you must have a Pokemon that knows the SURF HM, and a Pokemon that knows the FLY HM. Go to the old man in Viridian City that shows you how to catch Pokemon. When he asks you if you're in a hurry, answer NO. He'll show you how to catch Pokemon with a Weedle as an example. Fly immediately to Cinnabar Island. Then surf up and down in the coast that's on the right of the island. After some strange Pokemon appear, a weird one, called MissingNo., will appear, which consists of pure blocks of graphics with no sense. Catching this glitch Pokemon can wreck your saved game or glitch your hall of fame. If you make it faint, or just run, you'll have your item in the 6th position 139 times.
Bug: Do the MissingNo. glitch and then go to a PC in any Pokemon Center, and select "Pokemon League" in the menu to enter the Hall of Fame (you must have won the League already). When you enter, you'll notice that everything is screwed up, the graphics are just boxes full of graphic glitches, and many weird sounds can be heard. The game may become slow after this.
Bug: Go to any of the entrances to the bike route without a bike. Enter to the gate, and then go all up. Now go all left. When you pass right him, he'll say "Excuse me!" because he won't let you advance to the route. However, when he says this, press repeatedly left. You'll go left, and then he'll say that you can not enter the route. Keep pressing left, and you'll eventually enter the route. In this, you'll appear in a bike, even though you don't have one.
Bug: Go to Cinnabar Island without having the Key to the Gym. Surf in the coast that's on the right of the gym, then press left to stand in the entrance of the gym. The usual message "The door is locked" will appear, but if you notice, there's a man in the roof! After the message is shown, the man returns to his normal position in the ground.
Bug: At the beginning of the game there's a girl near your house that says she's raising Pokemon too. If you push her to the northern exit of the town, and attempt to exit it, Oak will come and will take to to his lab. Only that this time, because of the girl, you won't be able to follow him correctly and you'll trespass some buildings until finally becoming stuck in his lab's wall.
Bug: After you deliver Oak's parcel, go and battle Blue on Route 22. Then return to Oak, and he'll tell you about capturing Pokemon and he'll give you 5 Pokeball. This is a hidden text. However, in the middle of the text, it becomes glitched and scrambled. No wonder why they kept it hidden.Dr. James
Bug: Depending on your name, when making the MissingNo. glitch, you'll find some weird Pokemon in the coast, which can be Mewtwo, Golduck and so on. These Pokemon are not supposed to be there. Also, their levels can exceed the maximum of 100. For example, with the name RED, you can find a 132 leveled Mewtwo.