I like this one, but I'm finding it tough going, especially the submarine challenges.

Not looking for cheats at this point, just a few easy to implement hints and/or tips.

Much obliged.

the submarine challenges are quite hard and i got stuck on the 2nd mission. to do the 2nd mission have your sub at level 2 and wait for the destoyer to come to you, position yourself so your sub is facing the destroyer head on. when he is 0.4 metres away fire 2 missiles at him which he cant dodge and repeat with the other destroyers until all u have to do is take out the 2 big boats.