Rockstar co-president Dan Houser has said development of Red Dead Redemption has been "challenging", but insisted the wait will be worth it.
Speaking in the latest issue of GamesTM, he said: "This project has been long, gruelling and enormously challenging for us, despite our massive experience at making open world games, the big team we have on the project, our strong technology base in RAGE and experience of making Red Dead Revolver."
He further added: "For the game to be fun and engaging and everything we hoped it could be, we had to include a huge range of classic western moments - stand-offs, duels, stagecoach fights, gunfights on trains, hold-ups, bounty hunting, and so on.
"This is the strength of the game, but doing this in a seamless way in a massive open world was a huge challenge."
The game was due for release on April 27 and 30 for the US and Europe, but will now release instead on May 18 and May 21 in both regions respectively for PS3 and 360.