Sony's annual game summer sale kicks off this week, starting off with four PlayStation 4 titles. 

Dubbed this year as the Play 2015 lineup, the summer sale started yesterday with discounted prices for upcoming game titles in its current-gen console. In addition to the discounts, players can also get a 10 percent off coupon on the PS Store when they buy two or more titles. Also, those who are current members of Sony's promotions and rewards program PlayStation Plus will also receive additional discounts of up to 20 percent when pre-ordering titles under the Play 2015 list. 

One of the most noted titles that Sony included in the list is "Journey," since the game will be a cross-buy title under the Play 2015 list. What this means is that those who have already purchased the PS3 version of the game can download "Journey" on the PS4 for free. The current-gen version, developed by Tricky Pixels, will be launched on July 21. Not much has changed from the previous version of the title, at least in terms of gameplay – players will still start off exploring an unknown world. However, the game's performance and design have taken advantage of the PS4's capabilities, as players will experience the game in full 1080p resolution. 

The coupon code for the PS4 download of "Journey" for PS3 version owners will be sent digitally.

In addition to "Journey," three upcoming titles are also part of this year's PS summer sale. "N++" is a combination puzzle and platformer game that will be released on July 28. Meanwhile, arcade-style shooter "Galak-Z" that will come out on Aug. 4 is also included in the list, as well as "Everybody's Gone to the Rapture," a pre-apocalyptic PS4 exclusive that is scheduled for release on Aug. 11.  

The sale runs from July 14 to August 18.