This page covers the advanced systems and game mechanics of Hokuto no Ken. For information regarding the basic game mechanics, see here.
Exceeding the '3-Star Limit'
As stated in the Basic Mechanics section, the amount of stars you can take off in any given combo is capped at 3. However, there are some exceptions to this rule. The first and most common being combos from BD grabs, which completely remove the limit of stars that can be taken. Another way to remove more than 3 stars is done by making your opponent guard a max-charged Banishing Strike. This causes them to wall-bounce and takes away a star that is not included in the 3-star limit, making a 4-star combo possible. Finally, it is also possible to remove more than 3 stars when you start a combo on a dizzied opponent.
Although the 3-star limit can be exceeded, the rule that each specific star-taking move can only take 1 star per combo stays intact, meaning it is necessary to use 4 or more distinct moves(or utilize Grave Install).
Player 1/Player 2 Side differences
In Hokuto no Ken, there are actually differences between the two sides in the game, which manifest in several ways. Firstly, there can be differences in the ease of doing certain combos depending on whether you pick the 'Player 1' or 'Player 2' side when first starting the game. Mr. Heart is the only character who is affected greatly by this, having a throw infinite that is much easier to perform when he is 'Player 2.' The second main difference in the sides is that the way characters bounce off the wall when being comboed is actually different on the left and right sides. This difference is independent of whether you are 'Player 1' or 'Player 2,' and you only need to take into account the side you are facing. This causes certain combos to only be possible or require modifications depending one which side of the stage you are in.