While rapidly pressing X to perform a four or five hit combo, press X slow enough to jab, but not too fast to trigger the combo. This will cause the thug to fall into a repeating animation, leaving him completely vulnerable and without the ability to attack you.
At the main menu, hold down (A) + (B) on controller 2 while selecting Options. You can then choose how many lives you start with (up to 9) and the starting stage, as well as play at the Very Easy and Mania difficulty levels.
To avoid damage while being thrown by an enemy, press and hold UP and JUMP from the moment your enemy throws you until you hit the ground. This will make character land on their feet, sustaining no damage.
At the title screen, hold Right and B on Controller 1 and hold Left and A on Controller 2. Then, press C on Controller 2 with everything else still held down. Both players can then be the same person in 2 Player mode.
ACHIEVEMENT - HOW TO UNLOCK Pipe Wielder (5 points) - Wield the pipe in single-player or co-op mode. Knife Wielder (5 points) - Wield the knife in single player or co-op mode. Psycho (15 points) - Kill 10 enemies without losing your weapon. Perfect Boss (10 points) - Defeat the first boss without dying. Fourth Boss (10 points) - Defeat the fourth boss. First Versus (10 points) - Defeat another player on Xbox Live in a versus match. Online Warrior (5 points) - Defeat 10 opponents on Xbox Live in versus mode. Online Co-op (10 points) - Beat an online co-op game. High Score (25 points) - Score 800,000 points in one game with Game Settings set to Hardcore. Kill Jet (30 points) - Defeat the Boss "Jet" at the end of Stage 2 with Game Settings set to Hardcore. Hard Win (35 points) - Beat the game without using a special attack. Perfect Win (40 points) - Beat the game without continuing.