The game uses custom movement settings (movement_*) but they can be overridden by the player's minetest.conf. The game's movement settings are very important as the levels have been carefully designed around them. They are sensitive to any user overrides.
Currently, if any user override is detected, it triggers a modal warning message in the game, strongly suggesting to manually fix this. But this is not ideal.
It would be better if the game actually forces those movement settings, at least by default. It's ugly the player must manually fix their settings to make this game work. And then remove the glitch_check_movement_settings mod (which was surprisingly complex).
I don't know how to force Minetest to use the movement settings without resorting to ugly hacks (like literally changing the player's minetest.conf which is an absolute no-go).