I was trying to switch from WASD to ESDF because I'm a weirdo that likes the closer-to-home-row setup, and I somehow managed to bind keys in such a way that I can no longer progress though menus to undo this. I think it was either binding confirm and cancel to the only confirm key, or unbinding confirm, not sure which.

Deleting my config file fixed this, but you should probably make it so that confirm and menu-down must have at least one key bound to it that is bound to no other button, so you can reset the controls without deleting the config file.