Spelunker Jason is exploring a cave when his date wanders ahead and stumbles upon the headquarters of a rogue paramilitary organization called the Restoration. Naturally, they believe Jason’s girl is a spy sent to disrupt their vague plans to do something big. So Jason sets off to rescue her. What ensues is a slick modern version of the 8- and 16-bit Metroid games. Combat, for the most part, is fairly pedestrian: Aim with the right control stick, pull the right trigger, and the bad guys go down. Things get more interesting once Jason acquires better weapons, like grenades, and encounters more challenging enemies, like Guy With Shield. (Incidentally, Jason sounds like Uncharted’s Nathan Drake because both characters are voiced by actor Nolan North, who in Shadow Complex doesn’t even attempt to not sound like Nathan Drake.)

The game monkeys around with perspective, permitting enemies to recede into the background and shoot at you from their new vantage points. You can return fire by aiming the right stick into the screen. But this is trickier than it should be, especially during the game’s more hectic battles. It’s also annoying on a more abstract level, because enemies can head off into the background, and you can’t. You’ll spend the first few hours of the game seeing places you’ll want to explore—Where do those stairs go? What’s behind that red door?—but you can’t.

This perspective cocktease aside, Shadow Complex is a solid little platformer that’s surprisingly massive in scope. Unlike in the Metroid series, there’s never anything vague about your next objective. An easy-to-read map is always a button-click away, and your route is marked out with a clean blue line. Which is useful, since the game’s greatest pleasure doesn’t come from battling bosses or solving puzzles; it comes from exploring every last rat-hole, every vent, and every secret room in the bunker. In fact, there’s enough secret content here to practically fill another game, and if you aren’t observant, you’ll miss it completely. Call this the biggest little game of 2009 so far.