Many gamers will be settling down to play through BioShock Infinite today, some later than others if you chose to buy the physical copy of the PC version.One of the bonuses of completing the game is unlocking 1999 Mode, which can be described as an ultra hard setting. It’s not just a harder game mode, though, it’s both more difficult and a different experience.AdChoices广告1999 Mode is named after the release year of the game System Shock 2, which several employees of Irrational Games worked on, including Ken Levine. Just like that game, 1999 Mode will force the player to make decisions about specializations that cannot be reversed and could even render certain parts of the game unbeatable. Yes, 1999 Mode will inevitably force game restarts depending on your choices.If that sounds like the perfect challenge to you, the good news is you don’t have to complete BioShock Infinite in order to unlock the mode. Irrational has included an alternative unlock mechanism. You simply enter the well-known Konami Code.In the past, Ken Levine has said the game definitely wouldn’t allow the unlock to happen through a code, but he was either joking at the time or changed his mind. From the main menu you can enter the following sequence of button presses and the 1999 Mode will appear as an option:Up, Up, Down, Down, Left, Right, Left, Right, B, A (or O, X on PS3)On PC, it will be whatever keys you have setup for cancel and confirm actions to replace the last two button presses in the sequence.I suspect most gamers will want to play the game to completion normally before attempting 1999 Mode. But the Konami Code is there in case you can’t wait. It’s also a welcome addition to the game as it does change the gameplay dynamics enough to make it a different experience. It’s not just you playing the same game again only having to play better to survive.