tekken 5.1 was a small upgrade of the original tekken 5 that was not released on consoles and instead, was only on arcades. it contained different balance changes to characters of the original game. it also fixed the damage done when using fground moves, instead of ground moves doing 100% damage, they now only did 70% damage. the character health bars for this game is a different colour to the health bars on the original tekken 5.