I think I will participate in review competition, what are the chances to take place? And if I can participate twice making 2+ reviews?
There is always a chance to take a place in this bounty. The chances are zero only if you don't participate at all. Therefore, it all depends on your actions, your ability to write quality reviews and a little luck.
In bounty, you no longer need luck, but the desire to get company tokens for your work, and how it will be sold on stock exchanges is another matter