请看美亚的预购PC版解释，美亚应该也是发的 steam的 key吧，美亚解释是25号可以玩，

ma81994500

Pre-order NBA 2K16 on PC and get early tip-off weekend access : Pre-order your copy from Amazon.com today and get the early tip-off edition. The early tip-off bonus includes access to NBA 2K16 on September 25, 2015 (four days before standard launch on September 29, 2015).
Also receive 35000 in NBA 2K15 VC (sent to customers within 24 hours of order) + 10,000 in NBA Virtual Currency + NBA 2K MyTeam VIP Pack (3 MyTEAM Emerald Packs each with a guaranteed Emerald player). Customers will emailed codes within 24 hours of order fulfillment. Offer valid when shipped and sold by Amazon.com. Amazon reserves the right to change or terminate this promotion at any time. Offer will be extended to all pre-orders.






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This item will be available on September 25, 2015 at 12:00 AM US/Pacific
具体解锁时间