An interesting story and some new features built around traditional game play, it's good for a ... spin-off.
The story in PMD starts with you, the leading character, drifting to a Pokemon island after a strange sea storm. Surprised to see yourself transformed into a Pokemon, you have no choice but to make friends with some others of your kind and finally form a team to participate in Wigglytuff Guild. Your motive, of course, is to explore the surrounding caverns to discover the reason of your transformation. However, during this, another secret is gradually revealed: the Time Gear - a mysterious object with the ability to control the time flow and cover the planet with darkness. Unfortunately, there are others who also knows about this artifact. And then you start a rival stretching over the past, the present and the future against many other powerful foes, including legendary pokemons, to save the peace of this world and discover your own secret. An interesting plot with many surprising turning-points awaits.
Despite the absorbing story, you can not help feeling deja vu since game play of PMD really lacks innovation. As usual there are some questions preceding the adventure and by answering this, you will be assigned a proper representative pokemon among the familiar ones such as Pikachu, Charmander hay Meowth... You can also choose another as your companion for the following incidents. Afterward PMD quickly leads you to discovering the caverns. Semi turn-based Role playing rules continue to be applied when players can move freely and the battle begins on encountering hostile monsters. Everything must be done in turn, from running around the opponents to fleeing or attacking. Generally, the feeling is more like pondering over a chess board than fighting a rapid-fire battle.
A strong point of PMD is its various covern designs. Game provides a large number of caves, and even in the same cave, the traps and layout will automatically change after each time you discover it. At first, you can not change your companion, but later it's possible to choose one of the tamed pokemon to travel with. Thanks to the huge number of Pokemons, most of which are typical for this series, you will have to spend a considerable amount of time to tame and select a satisfactory assistant. The difference between Explorers of Time and Explorers of Darkness is still some exclusive pokemons that only appear in one version but not the other. However, you can exchange them with other players through Wonder Mail.
If your team is defeated in a covern, all your gold plus half of the equipments will be lost. However, game provides several useful features helping you avoid such a loss. Every time you lose a battle, it's possible to send a SOS message to your friend through Nintendo Wi-Fi Connection or Wii Message Board and wait for rescue. During this time, you can return to the cave to loot items but can't gain more experience through battle. It's the most considerable addition to game play.
Besides familiar game play, control, graphics and sound in this version are also ... too familiar. Though controlling character through touch pad is executed, it proves to be so inconvenient that you will sooner or later return to traditional control with buttons. PMD still uses many bright, spectacular colors but its graphics does not look better than a GBA game. Sound part does its job, but not impressive. If you compare these factors with the nearest orthodox version for NDS: Pokemon Diamond/ Pearl, it is easy to understand why this is just a spin-off.
So yeah, it's an average game on NDS, or call mediocre if you like to.