Sony have confirmed to Wired that they are working on bringing PS2 games to the PlayStation 4 via emulation. In an email to Wired, a Sony representative revealed that they are “working on utilizing PS2 emulation technology to bring PS2 games forward to the current generation.”
We would have personally liked to have seen PS3 games bring emulated on the PS4, however, this is more complicated due to the PS3’s custom hardware. This complexity was the reason why Sony introduced the PlayStation Now streaming service rather than emulation.
PS2 Emulation is already available on the PS4, but Sony kept that under wraps until it was spotted that the Star Wars bundle, included as part of Star Wars Battlefront on the PS4, included three PS2 titles running under emulation.