Let’s not romanticize this too much. The unofficial Tekken Tag Tournament 2 for PSP is janky. It crashes if you use Alisa’s chainsaws on the Falling Garden stage. The AI in Tag mode is either brain-dead or reads your inputs perfectly. It is not the definitive way to play.
Then Tekken Tag Tournament 2 dropped on consoles in 2012. It was chaotic, beautiful, and boasted a roster of nearly 60 characters. PSP owners felt left out. But modders looked at Tekken 6 on PSP and saw an empty vessel. They realized that the engine was similar enough to the arcade version of TTT2 to allow for a "reskin" on a massive scale. Tekken Tag Tournament 2 Psp
Note: This post discusses unofficial mods. Always own a legal copy of Tekken 6 (PSP) and Tekken Tag Tournament 2 (console) before attempting to mod. Let’s not romanticize this too much