The PS1 multitap is from USA so there might be some compatibility issue (PS1->PS2, NTSC->PAL) but the other one shouldn't have any issues like that. When I plug the PS2 multitap in I can use player 1 controller just fine and navigate the games menus, but I can't select the 2-4 player mode in the game, so the game doesn't detect controllers 2, 3 and 4. Where's the problem? The multitap obviously isn't broken as controller number 1 functions normally while it's plugged in.