This page contains all the known Glitches in Grand Theft Auto 1.
The Swimming Glitch
Some water in the game will not kill the player instantly. For example, if the player walks into a small pond, they will keep walking through it despite the water being a height which would usually kill the player. After about 5 seconds, however, the player will die from drowning.
The Building Glitch
Sometimes, if the player rides a motorcycle at top speed into a car, the motorcycle will jump up and the player may get stuck into any buildings they hit. The only way the player can escape is by killing themself.
If the player punches a policeman, then steals a taxi, the policeman will chase them. Crashing into something and damaging the policeman's car may cause him to get into the taxi normally as if he is a passenger.
Occasionally, if the player accidently hits a separate glitch and gets their car stuck inside of a building, random cars will begin to spawn outside of the building, even if the player exits the vehicle.
When the police are chasing the player, crashing into and flipping over another car then leaving the vehicle may cause the player to be immediately busted, even if no police are in the immediate area.
If the player drives a motorcycle so fast into a house that they glitch and get stuck inside, it is possible that they will be teleported to the ocean after 6 seconds where they will die from drowning.