Sony continues to add to the catalog of PlayStation 2 games that you can play on PlayStation 4. The newest addition, Jak & Daxter: The Precursor Legacy, launched today and you can pick it up on your PS4 or via the PlayStation Store's website here.
Jak & Daxter: The Precursor Legacy is priced at $15, which is in line with other PS2-on-PS4 games, which typically are priced in the range of $10-$20. It's not backwards compatibility, so even if you already own The Precursor Legacy, you have to buy it again to play on PlayStation 4.
There are more than 40 games in the PS2-on-PS4 catalog, with some of the others including Grand Theft Auto: Vice City and San Andreas, along with Max Payne and Psychonauts. You can see a list of all of them here.
Sony started bringing PS2 games to PS4 in December 2015. The PS2 games have been updated with Trophy support and are upscaled to 1080p. Additionally, games in the program also support PS4 features such as Remote Play, Share Play, Activity Feeds, and Live Broadcast, giving them something of a modern spin.