No insurance? Fine, you don't have to allow the players the option of insurance, but if the dealer ever has blackjack, you automatically loose. I just played a hand where the dealer had blackjack, and I was allowed to draw to a loss.
No Doubling down?
Not having these as part of the game makes me question how you programmed other basic aspects of the game such as how many decks you are playing with, and when they are shuffled. There should be either 6 or 8, so there should be a total of either 6 or 8 of every card before reshuffling.
Study up on blackjack a little more.