I was able to spend considerable time in Mission Mode during my session. I managed to get through a full Training session and clear the first stage and I got a good feel of what to expect from the central component of this game. In each area, you can choose from three different ship types. I toyed around with both the compact and mid-sized submarines but there's also a larger one as well. As soon as you get into the water, it's hard not to notice how nice the water looks on the top screen even without the 3D.
The Touch Screen contains all of your navigation controls and it's presented in such a way that you really get an authentic feel for what it's like to control a submarine. One gauge is used to control backward and forward movements, while another controls is used to travel up and down at a steady pace. Those are the main things you need to worry about. Your submarine is equipped with a handful of items, including vertical torpedoes for hitting carriers resting on the surface of the water, and missiles used to destroy rock barriers. In addition to avoiding contact with walls, you'll also need to be careful of rival subs as well as mines that float in the water.
Playing the game was very involved and engaging. It didn't take me that long to wrap my head around the system, and once you do, it captures your attention. When it comes to the 3D aspect, I didn't notice a big change in the overall depth of field, but maybe that's because the water effects were already good-looking in appearance. I'll definitely have to play around with that more when I try the game for myself to see if the 3D slider does make a difference in the way you see the game.
At the conclusion of Mission 1, there was a Periscope segment where I got to look above the surface and fire torpedoes at carriers off into the distance. This was really fun especially since I had to literally move around in my playing space thanks to the incorporation of the system's gyroscopic sensors. When you sustain damage, you'll get leaks of water appearing on the Touch Screen and you'll need to plug these using your stylus. Along the sides are handles marked "Zoom" and "Dive". I figure the latter is used to dodge missiles but I didn't actually make use of either of these during my session.
Interestingly enough, I was the only one out of everyone who tried the game that day who successfully completed a mission and set a high-score. In fact, even one of the Nintendo reps said they couldn't even play the game properly which was kind of embarrassing. I have a feeling some either gave up early on or skipped over it altogether, which is a huge shame. Honestly, I really enjoyed playing this game and I sincerely look forward to seeing how the final release turns out.