This game can be fun and challenging, but it is repetitive and can send you back several levels if you fail to complete a mission. It's a basic "arcade" game in that ships pass by your fixed point submarine, and you have to use various weapons to sink them. Your sub can swivel, so you can cover most of the screen when no obstacles (such as rocks) are present, but the aiming algorithm is off the further to "screen left" you go. You learn the tricks by progressing through various missions. If you do make it through an entire "career", the score reset function doesn't work, at least in Windows 8.1. I had to kill the program and use a different player name to get the game to continue functioning.