"Additional screenshots" refers to more pictures or images, usually provided alongside some existing ones, to further illustrate or give additional visual information about something such as a product, software, or webpage. Full definition
Once you've viewed the video, scroll down below the video for a few additional screenshots. (magnoliamedianetwork.com)
For more information, check out the trailer below, as well as additional screenshots, to see some preview of the gameplay. (droidgamers.com)
Today's Japanese news: teaser website and gameplay clip for The Alliance Alive, preview for the next episode of Monster Hunter Stories: RIDE ON (anime series), boxart for the SEGA 3D Classics Collection 1 — 2 — 3 Triple Pack, two additional screenshots for Yo - kai Watch 3: Sukiyaki, and gameplay footage for Puzzle & Dragons X! (perfectly-nintendo.com)