Got to level 9-1 and get the hidden Antique. Do this by going down one of the alleyways. There will be a pile of crates and a broken down bus. Jump on the crate and onto the bus. From the bus, jump onto the building . There should be two crates here, containing Pizza and the Antique. Then, complete the level and defeat all the Purple Dragons, Foot, and Mobsters. Next, go to the " 2nd Time Around". If you look through the different objects in the "NY" section, you will see the image of an arcade. Select the arcade to see information on it. When you exit out of the information, the message "Classic Arcade Mode Unlocked" will appear, and that option is now on the main menu at the title screen. Note: Do not worry if the screen remains black, or the arcade main screen takes a long time to load; this is normal.
In the arcade game, the joystick and certain buttons including the pause feature do not work. The character selection is just like the arcade. Each controller controls a different turtle. You cannot choose which turtle to assign to a controller. Controller one is Leonardo, controller two is Michaelangelo, controller three is Donatello, and Controller four is Raphael.