The PlayStation Vita’s Grand Theft Auto III port is based upon the re3 engine which is a open-source reverse-engineered game engine for the game. Initially starting their porting with the Switch’s re3 engine port, Rinnegatamante and TheFlow managed to make swift progress over the last week with the port going from not being able to display any 3D graphics to now being fully playable with only very minor issues being present.
Performance-wise, Rinnegatamante states that game never drops below the 20-24 FPS bar which provides an experience pretty close to the PlayStation 2 version of the game which runs at 25 or 30FPS depending on the console’s region. Thanks to this, the PlayStation Vita finally has a fully playable native Grand Theft Auto title running on it which will surely make a good deal in the community happy!

https://wololo.net/2020/10/28/psvita...-all-the-time/