At this point, Pokémon is less a franchise than it is a media juggernaut.
Pokémon Mystery Dungeon: Explorers of SkyPublisher: Nintendo
Platform: Nintendo DS
ESRB Rating: Everyone
Release Date: 2009-10-12
At this point, Pokémon is less a franchise than it is a media juggernaut. The sales success of anything Pokémon related is virtually assumed. In fact, there has been such a media assault of all things Pokémon in the past several years that it's sometimes almost difficult to remember that it started its life as (and somewhat remains) a well regarded video game series. It's arguable that the success of Pokémon helped to sustain Nintendo through the relatively lean years of the N64 and Gamecube. The core Pokémon titles are undoubtedly well-crafted role playing games that are surprisingly deep given their simplification of the traditional turn-based RPG formula. The addictive collection aspect pairs quite well with the simple rock/paper/scissors strategy of the fights, not to mention the fun of assembling an effective team. Not surprisingly, the success of the initial titles has led to multiple sequels and spinoffs.
Tie in games are generally slow moving targets for critics because by their very nature they serve as an effort to cash in on the time sensitive interest of a related product in a different medium. What makes the Pokémon brand interesting is that it is largely comprised of games that are tie-ins to other games. A good number of Pokémon titles are released in the downtime between core titles, clearly meant to sate the appetite of fans anxious to spend more time in this world. But as is the case with many tie-ins in general, these spinoffs are largely unsatisfying, largely missing the point of what makes the experience in the core Pokémon titles so appealing and addictive to begin with.
That's why it's difficult to characterize the newest Pokémon-related title, Mystery Dungeon: Explorers of Sky, as a disappointment. To do so would indicate that expectations for it were high, but by this point, hardcore gamers know that generally speaking they are going to get far more depth and enjoyment out of the core Pokémon titles than from the various other games bearing the Pokémon name. Further Explorers of Sky is actually a remake or director's cut of Explorers of Time/Explorers of Darkness, sister DS titles that were released in early 2008. While the Pokémon franchise as a whole is populated by remakes, and while these refined versions of games do make sense given the depth of the meaty core games of the series, it's debatable whether it's a worthy goal to offer slightly modified versions of Pokémon spinoffs. This publication ran a review of Explorers of Darkness/Explorers of Time when those titles were released, and the points made there still stand. Rather than rehashing them, then, I'd like to discuss the gaming arm of the Pokémon brand at large.
What's most surprising to me is that most Pokémon spinoffs can still be classified as role playing games. The Ranger series has a bit more of an action/adventure focus, the Explorers series is certainly more of a dungeon crawler, and the Stadium series is arguably more focused on strategy. There have been other efforts like the racing title Pokémon Dash, and the puzzle title Pokémon Puzzle League, but by and large, we haven't seen the kind of creativity and genre exploration that Nintendo is capable of, even given their long history of taking fundamentally sound and enjoyable gameplay concepts and using them to tell the same stories over and over again.
Consider the Mario brand. Nintendo has certainly not shied away from putting the cast of Mario characters in games not even remotely related to the platform genre that they came from. By and large, they've been successful in doing so, either bringing the unique flair of the Mushroom Kingdom to established genres (the Mario sports titles most easily come to mind), or pioneering new genres altogether (as is certainly the case with Mario Kart). This makes it difficult to understand the overall risk aversion with the cash cow that is Pokémon.
On the other hand, it may be the case that interest in Pokémon has fundamentally to do with the concept of collecting these creatures and forcing them into cartoonish battle with one another. As such, there may only be a discrete number of of ways to present them. Pokémon doesn't have an ensemble cast on par with the Mario clan. Arguably the only breakout star has been Pikachu. However, none of the Mario characters really had a personality to begin with either. Their richness as an ensemble took many years and numerous titles before such branching out was possible. Perhaps then, the Pokémon franchise's seeming inability to step outside of its comfort zone might paradoxically have to do with how little it has already tried. While it is difficult to argue that Nintendo doesn't know how to successfully monetize the Pokémon brand, from a gamer's perspective, it might be nice to see more experimentation with presentation within the brand.