The Hardware: Rivals Beta is available worldwide to all PlayStation Plus subscribers Hardware: Rivals is an arcade-style, vehicle combat game where you can get behind the wheel of a Tank or Fast Attack Vehicle, load up with devastating weapons, and hunt down and destroy your opponents.
Anyone with an active PlayStation Plus subscription is eligible to take part, and you can download the game from the Plus section of PlayStation Store.
During the Beta we’ll be letting in batches of players on a first-come-first-served basis. When you launch the game, you’ll automatically be granted a Beta key if one is available, and can start playing right away.
If all of the keys in the current batch have been taken, you’ll have to wait until a new batch is released. Don’t worry though, we’ll be releasing new keys regularly throughout the Beta, so keep an eye on the Official Forums for updates.
tldr: Go to PS Store on your PS4 and search "Hardware Rivals" and download. I believe its around 2GB. It's the same game that shipped with the online adapter for PS2 a decade ago. Game is still awesome.
Remember playing Hardware Online Arena on my PS2 back in the day.. holy sh*t, that was in 2002?!