why just tekken 6 work why not other work

[Adhenovan]

Each game assign different port to communicate through the adhoc functions so the result and port used is different for each game.

The game youre trying to play is not working often its caused by used port or blocked by firewall. Some game used privileged port on Linux and Android to workaround that issues you need to set port offset greater than 1024 on every ppsspp instance on the network.

I can confirm metal slug xx working with port offset.

there is also many adhoc function still untested. The original prometheus online server used by ppsspp is just compatible with 50+ games. If you're really want a game to work well contribute to the development by sending issues with log or write the fix by yourself. That how opensource works.