This game is a major rip-off, its all about the money you have to spend to get boosts in order to advance in game play. When you play from city to city, the monies you have earned are not able to be used, you start over. Each city gets more difficult and requires more upgrades and boosts. The money you have earned in game play can be used for upgrades... however you can't win the level without boosts. Do not play this game unless you have money to burn.