To all runners: This is an important rule change effective on 1/22/17; all newly submitted runs must include proof of difficulty setting. To do this, press F2 while in the game (while using MAME) to bring up the settings. While in this menu, select "Game Options" to display the difficulty.

For clarification, the difficulty should be set at 4. When it is, it will appear as GREEN, since it's the default difficulty.