Only a simple "offline" highscore, because an online highscore is much harder to make. With a highscore, the player has always a goal(to get a better score, than his best score). A goal for the player to follow is really important for these kind of games. That´s a basic Game Design Rule. But it´s definitely something different to now the Game Design Rules then really having the time to implement all of the features in the game. Believe me :D