||As a gamer that regularly demands innovation from forthcoming IPs, I always feel like a bit of a hypocrite falling back into the familiar gun-toting embrace of SNK Playmore's Metal Slug franchise. Here's a series of games that's hardly altered so much as a pixel since its 1996 arcade cabinet debut and has maintained a substantial fanbase precisely because of it. While the core run-n-gun mechanics have remained largely unchanged since day one, its the off-the-wall humor, colorful characters, inventive weapons, and zany bosses that have earned Metal Slug a special place in the hearts of jaded arcade-dwellers everywhere...Even for a series as consistent as Slug, there's a limit to what can remain unchanged before gamers start feeling just a little bit cheated. Case in point: Metal Slug XX is, more or less, Metal Slug 7; a year-and-a-half old Nintendo DS title stretched to match the PSP's 16:9 widescreen display with a few balancing tweaks, sound effects, and hidden routes thrown in for good measure. Where the original Metal Slug X was essentially a port of Metal Slug 2, X still introduced a bevy of new weapons, vehicles, and enemies -- all of which are now series staples. Metal Slug XX doesn't share its predecessor's innovation, but not for lack of trying; while the swapped weapon spawns and POW positions certainly add some much needed variety into Slug's tired formula, much of Metal Slug XX's single-player mission doesn't bring any new content to the table. Combat School also makes a return from Metal Slug 7, and while it doesn't bring along any new missions or levels, it does offer a new rank to conquer. Again, it's nothing incredibly deep or innovative, but it's nice to have something to come back to after the 40-minute campaign draws to a close...I can't really recommend Metal Slug XX if you're not already an established fan of the franchise, and in all honesty, I have a bit of trouble recommending it if you've already purchased Metal Slug 7. The stretched widescreen is sure to draw ire from fans of the DS iteration, and the five-to-seven second load screens in between areas can occasionally break the flow of the gameplay, but the excellent multiplayer alone is reason enough for a $20 investment in my book. Metal Slug XX isn't the best installment in the long-running series, and it certainly isn't the worst, but it still offers up an enjoyable experience that's perfect in bite-sized blasts -- preferably with a well-armed partner-in-crime at your side.