I've never played a Mysterious Dungeon/Fushigi no Dungeon game before, but if this Pokémon game is any indication, I'd like to play them.
Starting out, you play as a pokémon who is recruited by Pikachu into a rescue team, whose purpose is to help the helpless. This is about as far as the story got in the demo.
As a Mysterious Dungeon game, Blue Rescue Team has a very Dragon Quest feel. All actions are initiated by a menu system, though you have limited control of your companions. Pressing B will use a normal attack, but this usually isn't the best idea. Battles aren't exactly realtime, but they aren't completely turn based either. Every action, be it moving or performing an attack, is like a turn. If you're not doing anything, though, nothing happens, so you can plan your strategy. Beware that some enemies will run away before you can finish them. In such a case, you can use diagonal movements to get right back to them and finish them off. It's like a turn based RPG without random battles and with no auxiliary battle screen. As for your poké-allies, which in my case was the ever-nuclear Pikachu, you can adjust the skills it should use in battle, but this is the full extent of the control you have.
As dungeons are randomly generated (I believe), of course you'll need a map. This is done for you with a superimposed map on the main screen which grows as you explore the dungeon. A white dot signifies your character. A yellow dot signified Pikachu for my playthrough, though it could also denote all allies. Red dots indicated enemies.
Overall, the game looked like a lot of fun, and a nice, different take on the Pokémon world. I'd like to play this one again. Gotta save 'em all!