Roll7, the studio behind the sidescrolling skateboard series OlliOlli, was closed down after Take-Two Interactive's Private Division label was sold last year—announced after a lot of hemming and hawing from Take-Two's CEO. Presumably as a consequence of that, two games Roll7 made under Private Division, OlliOlli World and Rollerdrome, have both been delisted on Steam.
Roll7's earlier games, OlliOlli and OlliOlli 2: Welcome to OlliWood, both remain available on Steam as they were published by Devolver Digital. Surprisingly, so does Kerbal Space Program 2, developed by the similarly shuttered Intercept Games for Private Division. That could be evidence the label's new owners intend to continue supporting the early access game, or that its publishing rights weren't included in the sale, or could just be an oversight. Tales of the Shire, the upcoming Middle-earth life sim Wētā Workshop developed for Private Division, has also kept its listing.
