reaching the surface seems a bit confusing. points don't matter.  game does tell you how to get to the surface but having the view move upward and in the view show a boat would have given the game a lot more purpose. this may have been how the original game was played and if that was the case. this is an excellent port. responsive controls. tough difficulty that has a lot of unexpected things happened for killing the enemies. However the point values of the enemies do add a bit of risk and reward to the game. I went after the jellyfish and dodging the smaller ones and eliminated those to get the score needed to win the game.