Standard Tekken 3 is 4:3 letterboxed. On a modern 16:9 TV, it looks tiny. Using a PS2 emulator (PCSX2) running the PS1 ISO via PS1 BIOS, you can apply a widescreen code:
Unlocked by beating Story Mode 16 times; select him by pressing Start or Triangle on Eddy Gordo. tekken 3 ps2 iso best