At the risk of Cyril ostracizing me for mentioning another N64 title, I have to say this was the best rail shooter I've played since StarFox 64.
I'm such a big StarFox fan, in fact, that I bought my Xbox for Crimson Skies - the best "StarFox" game in years. But StarFox is really all Crimson Skies is, honestly. Just in all-range mode all the time. But Panzer Dragoon 2, is alike enough to draw me into the game when I finally discover that its actually completely different.
I remember playing the original Panzer Dragoon, and thinking how great it looks, and how I doubted that even a sequel could look any better. Boy was I ever wrong. The difference between Panzer Dragoon and Panzer Dragoon 2: Zwei is almost as noticeable as going from StarFox on the SNES to StarFox on the Nintendo 64.
Like the first entry to the series, you can rotate a complete 360 while still moving forwards, which is handy in making you forget, or stop caring that you're on a rail. But unlike the first game, this one allows not only different paths through the levels and different mini-boss encounters (boy, how long has it been that a game's actually HAD mini-bosses?), but your Dragon will evolves over the course of the game as well, depending on how successful you are. You start out running across the ground, and eventually launch yourself up into the skies.
Also, just for fun, the options included a "pandora's box" which was absent from the original game, and allows you to choose whichever type of dragon you want, whichever level of shots, etc. You can't save, of course, but it does help with replay.
Plot-wise, the game seems pretty straightforward. You're on a baby dragon, so go kill things. But I learned the game is a prequel to the original, which would seem to mean your character in Zwei is the one we see get shot in the intro cut scene in the first panzer dragoon game, and bequeath his flying steed to your character in the first game. And if the relevance on the plot cohesion between the first and second game interests you, then you will literally be knocked out of your seat by the third, and most amazing game in the series; Panzer Dragoon Saga.
If nothing else, you need to play this game so prepare yourself for Panzer Dragoon Saga, one of the most rare, and indisputably best games ever created. You don't need to play Zwei first, but when you run into the sunken shelcoof, or when you reach the ultimate state of your dragon, it will be far more meaningful to you. Not to mention, if you play Saga, you will almost definitely go back and play through Zwei, just to see any other little details you may have overlooked.