achievement_reset()
Returns: N/A
This function will reset all achievements back to their initial
values for the game. This function is provided as a debug
function and it is not recommended that you permit the
end-user to do this in your games.
if debug_mode
{
if keyboard_check_pressed(vk_space)
achievement_reset
}
The above code checks to see the game is in debug mode, and if it is pressing "space" will reset all the achievements.