Kingdom Hearts HD 2.8 Final Chapter Prologue was revealed last week at TGS, after rumors of a Kingdom Hearts HD 2.9 prior to the show. The previous ReMIX games were already a big of a mouthful, but nothing is even close to this one, but now we have a somewhat explanation for why it is 2.8.
Nomura explained how the HD remake of Kingdom Hearts Dream Drop Distance is worthy of technically being 2.6, following up on 2.5 ReMIX.
Kingdom Hearts Birth By Sleep was already 0.1, so the new followup episode already had the 0.2 in the name with Kingdom Hearts 0.2 Birth By Sleep: A Fragmentary Passage, so that puts us up to the 2.8 name already.
However, there is one other part included with the “movie” version of Kingdom Hearts χ in Kingdom Hearts χ Back Cover takes place way before and has no real connection to Sora, so he decided that this one would just be zero.
This is pretty typical for the often confusing Kingdom Hearts series, with a very confusing name in Kingdom Hearts HD 2.8 Final Chapter Prologue.
I’m still banking that they really just wanted to save one decimal point to use as a major compilation for PS4 with Kingdom Hearts HD 1.5 and Kingdom Hearts HD 2.5, along with Kingdom Hearts HD 2.8. Nomura has previously claimed we won’t get the other two collections on PS4, but he never said it couldn’t be under a new name like 2.9.