Just got home with this not knowing what to expect. I wasn't looking forward to the usual learning curve that submarine games usually require. I expected just an okay game. BOY WAS I WRONG! Right out of the box the game is completely intuitive and visually stunning. The thing that had my jaw dropping on the floor was the "periscope" game (one of three game types). You hold your 3DS up and in front of you like you're looking through a periscope...and it's JUST LIKE LOOKING THROUGH A PERISCOPE I MEAN TO TELL YOU!!! To look around you turn your body and your 3DS pans the view according to your body movements just like the real thing! It's incredibly fluid. The fun factor was fully engaged the first minute I started playing this thing. The underwater 3D effects pull you right into the game and it's best to play the periscope game standing up because you've got enemy ships everywhere and you have to do some quick 180's. (So much for playing on the toilet!) This game adds a whole new dimension (no pun intended) to game play. I love it and I expect it will be a favorite of most who buy it. The other game types are superb as well. The graphics are beautiful and just plain fun. This game truly shines and delivered far more than my expectations! AWESOME JOB, NINTENDO!!!!!
EDIT: Having played it a little longer now, I've found that the periscope mode missions are more like mini-games in a time trial format. They're short but sweet. For a submarine game, this mode, while very fun, doesn't offer any depth of gameplay (pun intended). You simply try to beat your previous score. However, it is a visual treat, especially when you select to do battle in a storm. It makes for a nice "quickie" game fix when you don't have time to get into the main game. This periscope mode seems to be more of an added feature rather than a part of the main game which is a side-scrolling "get me from point A to point B" without crashing or getting blown up, torpedo-launching, maneuvering-style adventure. I said side-scrolling game, but don't let that fool you. The 3D environment draws you in beautifully. Part of the fun of playing this title is just enjoying the visuals. (Oh...by the way...I'm a 55 year old, so serene visuals are appealing to me. I can't speak for the young 'uns.) I still stick to the 5 star rating. Carry on, men. And don't forget, "Loose lips sink ships!"
CORRECTION: Awesome periscope mode CAN BE PLAYED WHILE ON THE TOILET! (Whew!) After seeing another review I read that you can use the stylus to pan the periscope without having to stand. (I'm somewhat of an idiot.) It would have been a little nicer if they had provided a customizable button option, though. Launching torpedoes must be done with the right-hand buttons while using the stylus left-handed which is a little awkward for us righties. I was going to mention this to the captain, but the last crew member that complained was strapped to the periscope outside and taken for a heck of a ride. That'll be all. As you were...carry on, men.
ADDITIONAL EDIT: Well, the game just keeps getting better! Just played the turn-based portion of the game and WOW! I'm lovin' it even more. So, just to recap...there's the awesome periscope game; the missions game; and the turn-based game! This is really a 3-in-1 package. The more I play it, the more I appreciate the value I've gotten for my money! This is just one of those rare occasions where the developer decided to go beyond giving you your money's worth. I really can't say enough about how great this game is! It is just a beautiful package. I'll even go as far as to say it's the best title released for the 3ds so far. (I'm basing that opinion on reviews I've read of games I don't have plus my personal experience with the ones I do have which are Pilotwings, Asphalt, and Street Fighter.)