Mediocre at best
This is not a very well-designed game. The story, for one makes little sense. If it is supposed to take place during World War II, what army would be using arrows and balloons to defend and to destroy a bridge? Surely they would use aeroplanes that can get the job done more efficiently. So the whole premise of the game makes almost no sense.
The gameplay itself is poorly executed, as well. You should have the option of lateral movement, or at least rising above the bridge. I have no idea of why you would be using arrows if this game is supposed to take place during WWII: wouldn't you have a rifle instead?
The idea of defending a bridge is a good premise for a game. However, the manner in which you must defend it makes absolutely no sense.