The short answer is that, theoretically official, actually no, Abandoned is still not a Hideo Kojima game. In practice, however, things seem to be more complicated than the explicit statements of the developers that would lead us to assume.
As you know by now, the exclusive PS5 title of Blue Box Game Studios has been expressly declared as unrelated by the legendary Japanese game designer. However, in the last few hours, a lot of evidence is accumulating capable of dwarfing Smallville’s “wall of weirdness.”
Just the other day, in the list of features Blue Box Game Studios mentioned the “snowflakes of blood” that we will see in Abandoned, which on paper would have nothing to do with Hideo Kojima. In practice, however, Guillermo Del Toro used this specific expression in the past to define the now-defunct Silent Hill game.
Journalist Jason Schreier only recently expressed skepticism of Kojima’s involvement, with the tweet below. Nonetheless, until very recently he was one of the faithful supporters of what, until overwhelmingly proven to the contrary, remains a mere fan conjecture.
Alright after several hours going down the rabbit hole I am no longer 100% convinced it's Kojima (could very well be someone crafting all these coincidences to build buzz) but no matter what happens this will remain one of the most entertaining video game stories of the year
— Jason Schreier (@jasonschreier) June 18, 2021
While coincidences may actually be fictitious in order to create hype for Abandoned, they are far too many. Fans are noticing possible clues everywhere, an example above all Hasan Kahraman of Blue Box Game Studios: initials aside, translating the surname from Turkish to Japanese you get Hideo.
Another detail is the private message that Kahraman sent to Geoff Keighley about a possible reveal of the game as part of the Summer Game Fest. Aside from the very fact that Keighley has a screenshot of a private conversation, fans (and Schreier, before the tweet above) quickly linked two things.
Hideo Kojima has always been (unsurprisingly) a friend of Geoff Keighley, and the latter has started following Blue Box Game Studios on Twitter with at least suspicious timing. Furthermore, the social profile in question is the only web page of the development team: despite the ambition, there is still no official website.
What we can say with certainty is that, whatever these speculation lead to, this remains one of the journalistic stories- funniest video games of the year.