Metroid is a franchise that is almost unique. They're large, open-world games that encourage players to explore and advance at their own pace. Other games that borrowed the formula, like Castlevania, were never quite the same, as they were more focused on combat and RPG elements than the exploration. Sadly, Metroid has moved away from its 2-D roots in its recent offerings, with all the most recent games being first-person 3-D titles. Shadow Complex is a love letter to the old-school Metroid franchise in every way. While unconnected to Nintendo's franchise, it is built around the idea of making a Metroid game that isn't Metroid. The end result is something that many gamers have been waiting for since Metroid Fusion: a new 2-D Metroid-style game.

Shadow Complex is set in the same universe as "Ender's Game," author Orson Scott Card's "Empire" novel, which is set in present-day United States. The President and the Vice President have been assassinated, and the culprits appear to be a strange and highly advanced splinter group called the Progressive Restoration, who seek to take over America and lead it into a new era of glory similar to the Roman Empire. Shadow Complex opens up just before the VP is assassinated. Players are put in control of Jason Fleming, an average fellow who, along with his girlfriend Claire, go on a hiking expedition, blissfully unaware of the events. The pair ends up at a cave complex, which is secretly home to the Restoration's soldiers. Claire is captured, and Jason is forced to sneak into the complex and rescue her while attempting to thwart the Restoration's attempt to create a super weapon.

Shadow Complex is, at heart, a Metroid clone. The game isn't shy about this, and everything, from the basic gameplay to the in-game map, is heavily inspired by Nintendo's classic franchise. As such, you've got a pretty good idea of what to expect from Shadow Complex. The game is built like the classic Metroid titles and is a 2-D platformer. It's heavily built around exploration and finding your way through the mysterious complex while trying to find various items, equipment and power-ups to make yourself more powerful. The most notable of these is the Omega Suit, a special suit of power armor that enhances all of Jason's abilities and can be upgraded with special modules found around the complex.

However, in a deviation from Metroid, items are not your only way to level up. As you advance through the game, you'll earn experience points for completing various tasks. Killing enemies earns you a minuscule amount of experience points. You can multiply this by defeating enemies with headshots or melee attacks, each of which adds a temporary multiplier. The real way to earn experience is to either defeat the game's boss creatures or to explore the map. For every square of the map you explore, you'll gain experience points. For those who worry this means "grinding for levels," fear not. The abilities you gain from this are simply icing on the cake and aren't required to progress in the game. You'll simply gain small boosts to Jason's basic abilities, such as his accuracy with guns. Every 10 levels, you gain a more significant boost, such as a permanent increase to your health.

Combat in Shadow Complex is a touch different from the Metroid games. Like Samus Aran, Jason has a series of weapons that he can use. His primary weapon, the gun, has infinite ammo, though you'll occasionally have to pause to reload. In addition to his gun, Jason will eventually find grenades, missiles, a foam gun and various other weapons and abilities to use. With the exception of his main gun, Jason has limited ammo for all of his weapons. It's very similar to Metroid on the surface, but rather different under the hood.

Generally, combat has more in common with modern-day FPSes than Metroid, at least early on. The game is technically 2.5-D, and you'll have to deal with enemies in the background in addition to those to the left and right. You can also perform a special instant-kill melee attack on foes if you get up close and press the B button, something that Samus Aran could never do. Since you're facing heavily armed soldiers as opposed to random aliens and monsters, cover plays a much bigger factor in your game. You can duck behind boxes or metal plates to limit the damage that enemies can do to you and then pop out to counter with a burst of your own gunfire. However, as Jason gets more equipment, this starts to be less of a factor. Once you have a powerful Omega Suit, you can run through stages, blowing away enemies with highly advanced weapons while their bullets plink off your armor.

However, exploration, not combat, is the name of the game. The complex is a giant, wide-open area for you to explore at your leisure. There are multiple paths throughout the complex and more than one way to find your way around the giant maze. Hidden pathways and shortcuts litter the map, allowing you to discover faster ways through the complex or special hidden items and equipment to make your survival easier. There are even stealthy pathways through certain tough areas that allow you to sneak past enemies instead of fighting. Not everything is accessible to you from the outset, though. As in Metroid, certain doors or paths are locked to certain weapons. Fortunately, Jason's flashlight can reveal exactly which weapon you need for these obstacles. When you shine the flashlight on a breakable object, it will glow with different colors, each color corresponding to one of Jason's weapons or abilities. Once you have the proper weapon, you can return and open up a new path.

As in Metroid, you'll gain new abilities and upgrades to your Omega Suit as you advance through the game. Each ability allows you access to new sections of the game. Some of these are going to be quite familiar to fans of Samus Aran, as they are almost carbon copies of some of her most iconic powers. For example, the Friction Dampener is nearly identical to Samus' Speed Booster. When you have enough open space, you hold the run button and dash forward; Jason will begin to glow, and he'll gain the ability to dash through enemies and certain obstacles.

While a good number of Jason's abilities are borrowed from Samus, not all of them are. He has a few rather interesting and unique powers to augment his inventory. For example, one of Jason's weapons is the Foam Gun. In the context of the game, foam is a harmless and nonlethal weapon that's used by enemies in sensitive areas, where they don't want to risk stray bullets destroying important objects. That doesn't mean that it doesn't have its uses once Jason finds a Foam Gun upgrade. The foam halts anything in its tracks, so it can be used to stop fast-moving platforms, slow down enemies, or even force certain doors to malfunction. The foam gun also serves a second purpose: Repeated shots of foam will stick to walls and quickly harden to form temporary platforms. This allows you to access areas in the game earlier than you should or even forgo entire segments of the game if you're going for the game's Achievements.

Metroid fans will be very glad to hear that Shadow Complex is built around the "sequence breaking" gameplay that many fans of the franchise find so appealing. For those unfamiliar with the concept, Metroid fans would try to figure out the best way to finish a Metroid game with as few items as possible, or as quickly as possible, through a method called "sequence breaking." This would involve using careful timing and hidden skills to get through areas that aren't normally accessible until later in the game. In some cases, it involved glitches, while in others, it was intentional. Shadow Complex follows the same design formula, and players who beat the game as intended may find that they've only just begun. The title will reward players who find the fastest way through the game or who intentionally limit themselves to certain items. The hardest challenge in the game will involve players only finding four items in the entire game! Shadow Complex also features a "proving ground" set of challenge rooms outside of the main game. These rooms challenge players to complete certain tasks with a limited inventory. The fastest times are placed on Xbox Live leaderboards to allow players to compare their best times with other gamers around the world.

Shadow Complex isn't exactly Metroid, but it's the closest thing that we'll get until Nintendo decides to make another classic-style Metroid game. Every element of Shadow Complex is a love letter to Samus Aran, from the main character's Omega Suit to the large open world to explore. There are some original twists and turns to be found, but by and large, the game prides itself on being a Metroid clone. If you're a gamer in the mood for an old-school Metroid title or simply someone looking for some high-quality 2-D exploration and platforming, you'll want to check out Shadow Complex when it hits Xbox Live Arcade next week.