The fixed 500BC debt limit does not make sense when your economy gets large! If I am turning in a surplus of >1000BC per turn then why is my production shutdown if while spending my surplus I accidently exceed the 500BC debt limit! The debt limit should be relative to GDP! Also, you should not be able to spend more than the debt limit or a dialog box should pop up a warning you that are going to exceed the debt limit. This would eliminate all those times I accidently exceeded the limit and needed to reload the game!