Started up the steam version in ASCII, and none of the 'P'lay, 'S'ettings, or 'C'redits options worked. Switching to tiles with F10 revealed that the issue was the popup about adom.cfg getting replaced.

EDIT: The same holds true for the explanations of game modes. So if you press 'T', 'W', 'X' etc. on the main menu in ASCII mode, it the game appears to be frozen.