Complex sentence: Sometimes the starting player has a minimal advantage, but Paper Soccer's competition is significant when more lines are drawn on the board, since players can make bounce moves and they have an opportunity to better maneuver their opponent.
Split into simpler sentences: Sometimes the starting player has a minimal advantage, but Paper Soccer's will be more a game of skill when more lines are draw on the board. Since players can make bounce moves and they have an opportunity to better maneuver their opponent.