There are a few holes in the Big Bang theory. First off, Why is gravity suddenly a repulsive force? Then, why do we think that because the universe is now expanding that it always has expanded and it will continue expanding? But those can be explained that the particle was so small and that the energy that lets it expand now had to come from somewhere.
Then here is my two big questions: how could time be nonexistant before the big bang? that does not make sense to me. Then, how did the original particle get there in the first place? if it was so small to begin with, how could it have lasted for any amount of time at all? How would gravity pull it together into one place if it is gravity that makes it explode in the first place? In other words, what happened in the 0.00000000000000000000000000000000000000000001 second before the big bang? (Why that particular number, anyway?) Other than that, it makes sense. To be fair, it runs into the same problem all other physics runs into, when you ask what makes the laws of nature laws to begin with. You will never get an answer to that question because there is a question behind that answer, and a question behind that answer, and a question behind that answer, ect, ect, ect, ad infinitum.
Personally, i believe the big bang was the creation. "And the spirit of God moved upon the face of the Deep."