New Delhi: Grand Theft Auto V, Rockstar's latest open-world adventure, is the fastest ever entertainment product to reach $1 billion sales - hitting the magic number in just three days. GTA 5, which was developed by Rockstar North, has been five years in the making and reportedly cost around $250 million.Released on September 17, 57 per cent of sales were for the Xbox 360 version of the game, with the remaining 43 per cent going to the PlayStation 3 edition.Online retailer Amazon sold out of the game on pre-orders alone.The new game has received rave reviews from critics across the board, including The Mirror, who have labelled it "one of the very best video games ever made" .Grand Theft Auto Online, the multiplayer portion of the game, launches this October, which may help push the game's sales to even greater heights.Here are the five reasons why you should buy 'Grand Theft Auto 5:1. Best GTA soundtrack everGTA V's soundtrack features the usual array of high-quality tracks licensed from across the genre spectrum. There are the 240 licensed songs that make up GTA V's persistent playlist. Bootsy Collins, Kenny Loggins and Pam Grier serve as the DJs for three of the game's 15 radio stations, which cover a range from rock and pop to Mexican electronica (a real thing).2. There are aliensGTA V reveal a UFO-related accomplishment. You'll have to play the game to find out.3. It cost over $130 millionThe game cost more than most Hollywood blockbusters. 4. There are sharksThe GTA V promises environment like submarines, flora, deadly fauna and an underwater kingdom for players used to just scratching the surface. 5. There are three main charactersCharacter 1 – Michael, an ex-bank robber in his early 40s who retired after making a deal with the FIB. He has two teenage children and hates his wife Amanda. He's also the narrator of the original GTA 5 trailer.Character 2 – Trevor, a former war veteran and a “drugged out psychopath”. An experienced pilot.Character 3 – Franklin, a repo man in his mid 20s described as a “young and ambitious hustler”.That you can switch to on the fly. And if you're taking control of Michael, Trevor and Franklin will continue on with their lives, meaning the next time you jump into an alternate character, you could be in the middle of a street race or just coming home to the family.