At the title screen, press up 12 times, then press START. Choose optios, then go to the exit option and press Down one time. After the highlight disappears from the bottom of the stage, press C. You will now be able to pick the ring size.
At the Title screen, choose either Arcade or Vs mode. This will work in either One or Two player modes. At the Fighter selection screen, press Down, Up, Right, A+Left (D.U.R.A.L.).