The Dev Team Thinks Of Everything: Grand Theft Auto
Grand Theft AutoSan Andreas is chock full of this. No matter where you go, there's something there that evidenced the dev team thought of it first: tunnels just big enough to get a helicopter/VTOL jet through, others with things that make it just the wrong size, parachutes in high places, and even a sign atop a bridge saying, 'There are no easter eggs up here, go away.'
In Grand Theft Auto IV you get a mobile phone. If you're in a car listening to the radio when someone contacts you, the car speakers skip just before it rings, as often occurs in real life.
GTA IV has this in spades. The subway stations have performers at rush hour that you can tip. You can meet a girl on the in-game internet, and after your dates she will blog about them. You can even take the Roosevelt Island tram ride.
Not to mention the meeting up with friends to play pool, go bowling, get drunk, even drive drunk which immediately causes the cops to chase after you and your character to say it might be a bad idea. When you haven't seen a friend in a while their dialogue will be different to if you see them often. In the expansions, you can play air hockey and go to the nightclub for drinking games. The only thing the developers didn't put in was what made the previous San Andreas so good, which is the enormous countryside area outside of the city, including rural areas that have no function within the game and are just nice to drive through. There is also the issue of customisation being limited compared to San Andreas. However they clearly spent less time on these to put more focus into the story, the player really getting a feel for the characters.
In addition in GTAIV, on the Statue Of Happiness, there is a hidden door which can only be accessed by helicopter. Walking through it (the door does not open and can literally be walked through as if it were an archway) you find a long ladder which leads up to a huge beating heart. In other words, the Statue Of Happiness is the heart of Liberty City, much like the real life Statue Of Liberty is considered to be to New York, which Liberty City is based on.
In Grand Theft Auto 3, there is an enclosed area limited by 4 high walls. If you manage to jump over one (with the help of a tall vehicle, for example), you can read the text "You weren't supposed to be able get here you know" on one of the walls.
In the PSP version of Liberty City Stories, there is a new sign in this alley, with a goofy smiling face with outstretched arms, and the message "Hello again!" In the PS2 port of LCS, the sign reads "You just can't get enough of this alley, can you?"
One mission in GTA 3 has you following a target of interest as he gets driven around by a taxi. Normally, you are supposed to keep your distance or you will scare the target off. However, if you kill the cab driver and take his place (or ram the taxi out of the way with one of your own), the target will get into your taxi and you are the one that drives him to his destination! You still have to kill him afterwards and he will still get spooked if you drive too recklessly.
Since the beginning but especially since well known songs came in Vice City, the radio stations have been like real life stations, playing licensed music, with their own presenters, stories and details of events which can be seen taking place in the game universe, even having different shows at different times of the day. It's such a detailed world that it got its own trope page: GTA Radio
