Oni 2 (Angel Studios)
Oni 2: Death & Taxes (working title) was a sequel to Oni which was in development from 2001-2002 before being cancelled. The game was being developed by Angel Studios under publisher Take-Two Interactive before Angel was acquired by Rockstar and renamed Rockstar San Diego. An ISO of the last (?) development build of the game leaked in 2016.
Development
Shortly after Oni was released, it was rumored that Take-Two had put Oni 2 into production; however, no sequel was ever officially announced. In 2007, the rumor of a cancelled sequel was bolstered by a leak which asserted that Oni 2 had been under development by Angel Studios for the PS2.
In 2016, the full story finally came out when an actual development build of the cancelled game was leaked and documented by the game preservation YouTube channel PtoPOnline here. Interviews with former developers revealed that the game had probably started development at the beginning of 2001 or even as early as late 2000, which would mean that its development overlapped with Oni's. Since the development build is dated Dec. 10, 2002, that means that the game was in development for as long as two years. After all that time, it was apparently not even close to completion. The project suffered from a lack of clear direction, and when Angel was acquired by Rockstar and renamed as Rockstar San Diego in 2002, Oni 2 was cancelled in favor of other projects.
Controls
Explain how to play the leaked build here.
Story
Put plot summary (is there a plot?) here.
Analysis
Andrew Borman (host of PtoPOnline) states that Oni 2 ran on a Renderware-based engine which Angel used for their other games. Since Angel mostly (in fact, almost exclusively) developed racing games, it's difficult to understand why T2 assigned them a third-person brawler with a heavy focus on bipedal animation.
Put engine analysis here.