First of all, if you enjoyed any of the previous titles (Red/Blue Rescue – Explorers of Sky/Darkness/Time), you will enjoy this game.
The storyline starts out as it did in the previous games – you're human that's turned into a Pokémon. I felt that the plot in this game wasn't as strong as it was in the Explorers games, yet it is still enjoyable to play. There are a few twists along the way, and also a few memorable characters too.
This game gets rid of some crucial elements from the old games, such as the Hunger feature. This gave the game a sense of realism that is now missing, yet it would certainly make the game more enjoyable for the younger audience.
Another bad point about this game is that you are truly restricted with the Pokémon you can get. There are a few from each Generation before the fifth (literally 3 or 4), and you can't even get all of the Unova Pokémon!
I also felt that there was a lack in dungeons. It is true that there are DLC dungeons coming out. However, there are only 12 of these, and these don't introduce many more Pokémon. This game also lacked the Legendary Pokémon bossess from the previous games, with only a few.
However, this game introduces a number of new features. The first is the Magnagate feature, allowing you to use your 3DS's camera to scan round objects to find new dungeons, which I suppose makes up for the lack of Dungeons in game. However, a mistake they made is that you are given random Pokémon to enter these dungeons with, not ones that are in your team. This was disappointing, but the feature is still enjoyable. Also introduced in this game is the Pokémon Paradise. This is an addictive feature which allows you to find building materials from completing Dungeons, and using them to build your ultimate Paradise.
In conclusion, I believe that this game is a great addition to the Mystery Dungeon series, but is aimed at a younger audience then the previous titles. Because of this, they have dumbed down the game a lot. I would still recommend purchasing this title, as I have throughly enjoyed playing it!