Build a bridge using your mouse and available budget. When it is done click "Test your bridge". Your workers will use it to get items located at the other side of valley, and bring them back to the shop. Your goal is to collect all items in level.
For each level you have limited budget. All money that you won't use, become your score, so cheaper bridge equals1 higher score. Money collected in all levels of game will be your total score and will be sent to leader board. You will use those money in challenge mode too.