As SNK has confirmed, “Metal Slug XX” will be released on PlayStation 4 in the summer of 2018. You know the title of the PSP.
Metal Slug XX is based on “Metal Slug 7” and was first released in 2009/2010 for the PSP. The title was also released for the Xbox 360 and the 3DS. The XX version includes Leona Heidern from “The King of Fighters” as a playable character and a co-op mode.