After no small number of rumours and insider reports, Sony have now added the ability to download PS4 and PS2 games via PlayStation Now and play them on your local PS4, in addition to its bread and butter of game streaming.
There’s a few wrinkles to this, so while you can play offline, your PS4 will need to get online once a week to check your subscription. You won’t need PS Plus to play PS Now games online, but you will need PS Plus to be able to take progress from a game you were streaming to that same game on your PS4 – you have to transfer from PS Now to PS Plus, and then to your PS4.
This also comes with the caveat that it’s only for PlayStation 4 and PlayStation 2 games, which can all be bought and played separately, but that didn’t stop plenty of people complaining on social media that it doesn’t include the PlayStation 3 titles on the service. Here’s the thing: that won’t happen because the PS4 architecture cannot feasibly emulate the PlayStation 3 architecture. The complexities of the Cell CPU and how many GPU image processing tasks were often offloaded to it from the GPU mean that Sony cannot mimic the Xbox One’s backward compatibility to Xbox 360.
Source: PS Blog