At the tertiary level, there are what Kant calls physicotheological arguments. These take as their starting point a particular feature of the world (e.g. apparent design, order, etc.) and argue from these to the existence of a God responsible for these features. Kant is unimpressed, suspecting that any argument of this sort must secretly depend on a cosmological argument. No one would begin to look for explanations of particular features of the world unless they were convinced already that the world as a whole required explanation.
The cosmological argument represents the second layer in the traditional proof for God. It proceeds, not from any particular aspect of the universe, but from the existence of the physical universe at all. In other words, it sees God as the answer to the question "why is there something rather than nothing?". Kant is equally dismissive of this argument. He believes that is essentially a cover for the ontological argument. No one would feel the need to posit God as an explanation for the world unless they already considered the notion of a necessary being to be coherent, and to require the actual existence of such a being.
At the most basic level, there are ontological arguments for God. These move from the concept of a necessary being, arguing that by definition the most perfect being must exist. Kant refutes the argument by asserting that existence simply is not a predicate and does not work in that way. In this opinion most philosophers have followed him. I'm not so sure myself, but I'm certain on other grounds that any form of ontological argument must ultimately fail.
In this fashion, Kant dismisses all traditional natural theology. You could argue that in fact what Kant shows is that one only finds God at the conclusion of the traditional theistic proofs if one is already predisposed to seek him there. This is the death of natural theology as traditionally conceived.
A question I would put to fellow Christians is whether they are content to take these arguments seriously? Are they prepared to leave natural theology behind? Note that this is something that we have to do even if we find the arguments convincing. Because of course we would find them convincing. We are looking for God, and lo and behold there he is. If you find design in the world around you that requires explanation, fair enough - so you should! But if your Christianity needs this philosophical foundation, I honestly think you're in trouble.