BASE Jumps are an optional side activity in the second Grand Theft Auto IV episode The Ballad of Gay Tony. There are a total of 15 BASE jump locations around Liberty City that are required for 100% completion and for the Gone Down achievement on the Xbox 360 and the same trophy on the PlayStation 3.
The first game in the Grand Theft Auto series to feature Parachutes and BASE jumping, to a somewhat lesser extent, was Grand Theft Auto: San Andreas although the activity is not as structured as it is in The Ballad of Gay Tony and is not required for 100% completion, although like TBoGT the parachuting mechanic is used in a few missions. After all 15 BASE jumps, required for 100% completion, have been completed, a parachute will spawn in Luis' safehouse for player use as desired.
In the minigame, there are locations found throughout the city where the player can find. If they are located, they are specified in three types of BASE jumps. Note that the base jumps have different difficulties but mostly remain simple. Target Jumps are the most common, and probably the easiest. Vehicle jumps sometimes tend to be the hardest because the jump must be made on a moving target. The vehicle target is a slow-moving Flatbed (except in one base jump where it is a Marquis boat).
Players should also be aware that when in a helicopter and you have a parachute, sometimes it may not appear and you will just fall; however, this can be fixed by selecting the parachute on the D-Pad and click RT. This spawns the parachute on Luis' back and is ready for use.
Overall, BASE jumping and skydiving are great ways to see Liberty City from great heights. BASE jumps are also available in Multiplayer, although they only move you to the top of a tall building, rather than being airlifted above a target by helicopter.
The most common type of jump which usually involves jumping off the tall buildings of Algonquin and going through checkpoints. As usual, the landing point is on the streets below after the checkpoints are collected. One jump includes jumping from the Rotterdam Tower and landing in the City Hall park.
The same as the target jumps but the landing point is a moving or a stationary vehicle. Some vehicle jumps also include using a Sanchez motorbike to propel the player towards a farther-away target where it is impossible to reach when jumping from the same building on foot. The National Newark Building is a Vehicle Jump Location.
Also the same with the mechanics of target and vehicle jumps but the starting point is in a helicopter. The LC24 Tower is one of the Helicopter Jumps.