Sometime over the last decade, when I wasn't really looking closely, all videogames went 3D. All of them. RPGs went 3D. Turn-based strategy games went 3D. The Prince of Persia went 3D. Metroid went 3D. Even Mario went 3D. At first, I was pretty sure it was wonderful. Now I'm not so sure, particularly when I come across something wonderful and 2D. Space Invaders Extreme, Patapon, and Castle Crashers, for instance.

So it's a relief to see a game like Shadow Complex, rendered in full-blown 3D, but played in wonderfully manageable 2D. It's like the new hotness in graphics combined with the good ol' days of gameplay.

Read the review after the jump.

So Shadow Complex is basically a Metroid game from the 90s. It's not even trying to hide it. You move right and left. You jump. That's pretty much it. You get weapon upgrades that also serve as keys, unlocking new areas. The map might as well be drawn on graph paper. You don't start out with a Samus suit, but by the time the game is done, you'll be closed up in one. Backgrounds are pretty amazing, but they're always and only backgrounds. It's the 21st Century equivalent of parallax scrolling. You do not, however, roll up into a little ball.

If none of that made any sense to you, all the better. You're in for a treat. There's a reason this is a tried-and-true type of gameplay. It's a slick balance between combat and exploration. The combat is simple, but as gratifying as any shooter, particularly as you get more types of guns. There are cover and aiming. There are physics as grenades knock bad guys into and over rails. Sometimes a robot falls on a dude and explodes, killing him. Melee kills zoom in to prove that, yes, this is 2D gameplay but these are no 2D graphics.

The game is full of great touches. On a couple of occasions, you fight a giant mech crab thing. When you win, it crumples on its broken metal legs, a defeated pile of junk. But wait! It's not dead! A panel opens and a dazed driver pulls himself through the hatch, firing at you half-heartedly. How satisfying to get to shoot the little man behind the curtain.

You also get what has to be the most useful flashlight in the history of videogame flashlights. Use it a bit like a cursor, moving it around the screen to highlight convenient color coding for places you can blow open with different types of weapons. Of course, it's also great for lighting up dark areas. You'll work your way through plenty of them.

In fact, Shadow Complex is a wonderful name for this game, and not just because you're skulking through dark areas. You're exploring a secret base, hidden secretly in the woods and full of secret things. On the narrative level, these secret things are related to an Orson Scott Card book, but you'd never know unless you looked it up on Wikipedia like I did. More relevant are all the secret doors and secret upgrades and secret collectibles that lead to secret features. Thanks to fully 3D graphics, lively artwork, gorgeous lighting, and superlative animation (swimming excepted), it's a joy to move around this secret base, plumbing its secret depths and plundering its secret goodies.

And for the Metroid/Castlevania impaired, there's always a blue line that shows you just where to go if you don't feel like exploring. For all the secrety bits in this shadow complex, it plays just fine as an obstacle course from point A to point B. Like all the best exploration, it's strictly optional and often off the beaten path.

This isn't the first attempt at this type of 2D gameplay in a 3D engine. For instance, the NES classic game Bionic Commando was recently remade as Bionic Commando: Rearmed (not to be confused with the wretched fully 3D Bionic Commando game). And while it was a decent game, it wasn't anywhere near as smooth, accessible, and generous as Shadow Complex. Bionic Commando: Rearmed was for fans of the old 2D exploration games. Shadow Complex is for everyone.

(Shadow Complex is an Xbox Live Arcade game available for download for $15.)