The study of real-option under competitive circumstance-the so-called “option-game”, has been experimenting a fast development recently. It shows that it is the same important to consider the interaction under competition for the investment decision besides the key factors such as uncertainty, flexibility. Based on existent literature, we analyze a model of duopoly under uncertainty assuming that investors are asymmetrical-both on revenue and cost. This paper provides some new insights and extensions about the investment timing in such a real estate development market.