Q*Bert Controls
Q\*Bert is a 4-way game where the joystick was mounted like an X. There is no way in MAME to make a diagonal (in other words 2 keys pressed at once) to be a direction to compensate. So to play it you will want to play it with that in mind, Up=up-right, Down=down-left, Left=up-left, and Right=down-right.
Source article: <https://support.xgaming.com/support/solutions/articles/12000054522-q-bert-controls>