I have also asked the developers about mining. There will not be any difficulty attributed to PKT. The PlayKey ecosystem will allow gamers to pay miners (owners of high end computers with GPUS) via smart contract to play games. This payment is via PKT tokens. So the idea of mining in this case is different from conventional mining whereby the supply will keep going down and difficulty will keep increasing as more miners get on board
RE: What PlayKey is doing will let anyone play PC Games without a High End Desktop