So why did Chair opt to pursue a Metroid-style adventure for its second Live Arcade title? We sat down with Chair Entertainment creative director and co-founder Donald Mustard to find out. And to thank him.

"It seems like there was this huge void," Mustard said, saying that Shadow Complex explores a largely unexplored genre. "No one's making these kinds of games. So we decided, well, we're gonna try it. My biggest secret hope is that some awesome game designer will look at what we did and think 'I could do that even better,' and make a game that I can play."

"I already know where everything is in Shadow Complex, which ruins it for me," Mustard joked.

One thing, though. Someone is making these games, as Koji Igarashi and the Castlevania team regularly pumps out "Metroidvania" games on Nintendo's portable platforms. But Chair didn't look to Igarashi's creations, instead going to the source.

"We really looked at Metroid more than Castlevania," he said. "We made everyone replay Super Metroid, Metroid Fusion and Metroid: Zero Mission. Everyone on the team played that for a week or two, but I played them constantly... to the point where I had felt like I had cleansed my system of anything other than Metroid."

Mustard said he was cognizant of looking too closely at the inspiration behind Shadow Complex's game design, saying that there's "a fine line between doing a genre entry and doing a genre rip-off." After immersing themselves in Metroid, they avoided the title during Shadow Complex's two year development cycle.

"We sat down, talked about what we wanted the game to be and we started designing what we thought it would be — then we never looked at Metroid again," Mustard said. "Because we then wanted to make our own game. And I think it was pretty effective, capturing that vibe of Metroid. We didn't want to be seen as derivative."

What games like Super Metroid—and most Metroid games—didn't offer was much of a narrative, at least not on par with what we're expecting to see in Shadow Complex. That's a potential pitfall, considering how much time is spent backtracking and exploring, things that may interfere with a game-long story line.

"I think you have to tell the right story," Mustard says. "Because so much of that kind of game is exploratory, and if you're doing it correctly, has a strong non-linear element to it."

Of course, there is a Metroid exception.

"Metroid Fusion had a really strong story to it," he notes "That's one of the ones I looked at the closest. I thought, 'What are the pitfalls that they fell into while doing this?'"

"I think we tried very hard to structure the narrative more about a loose plot, but then kept it very character-centric. We were always trying to keep the narrative flowing."

Mustard is obviously concerned about being compared unfairly to the decades old Metroid series, lamenting that "we can't compete with nostalgia"—words borrowed from our own Stephen Totilo.

We'll have more from our interview with Chair at Comic-Con later this week.

I've spent two hours and twenty minutes this morning with the game, a game made with great love for its predecessors. And no, of course it's not as brilliant as Super Metroid — what has the cleverness, the pacing, the geographic diversity, the unusual mix of power-ups? But it's clearly a game built on the same values. It's a game made to be played like it's a map being traced with a finger, followed closely, fueled by the excitement of where to explore next and where to come back to later.

Here's how it is shaping up so far…

What Is It?
Shadow Complex is an Xbox Live Arcade game set for release when it's steamy outside, an August alternative to the heat. It is a side-scrolling adventure game in the style of 2D Metroids and Castlevanias, but rendered with a 3D engine. As with its inspirations, it is a game about exploring, finding power-ups and using newly enhanced abilities to reach previously inaccessible areas of the map. This one's all about a guy fighting his way through an enormous underground sci-fi military base and, so far, trying to keep his girlfriend alive. It comes from Chair Entertainment and parent company Epic Games, chiefly designed by Donald Mustard with oversight from Gears of War alpha-developer Cliff Bleszinski. It's a 1200-point game, costing $15 and the build I downloaded, which appears to be final, is close to 900 MB.

What We Saw
I was supplied with code of the game that appears complete. I played the first two hours and twenty minutes, discovering 32% of the game's expansive 2D-map and finding 20% of its mostly-hidden power-ups.

How Far Along Is It?
The game appears to be done, but because it's a downloadable, it's probably eligible for more last-minute tweaking than most.

What Needs Improvement?
Too Much Nostalgia: One of the themes of Kotaku's coverage this week has been developers' love of past influences and the extent to which that love can be applied too thickly. Shadow Complex's first hour is almost a sequence of homages to sequences from Super Metroid, Empire Strikes Back and other boys-will-be-boys action-packed inspirations. Evoking the past so much is risky, especially given that this game's chief interactive predecessor is considered one of the greatest games of all time. That the early action in the game is more conventional and its environmental puzzles less interesting than Super Metroid's initially sets Shadow Complex needlessly back. It's only when Shadow Complex starts getting past the early homages and starts showing off its own ideas that it demonstrates its worth. (That first hour isn't helped with its Uncharted homage. Yes, you have the voice-actor, but did you also need to dress your guy in the half-tucked shirt?)

Ledge-Grabbing: The controls are mostly good but compromised in one common way: it's hard to sometimes know whether you're going to drop from a ledge or just hang from it, whether you're able to pull yourself up from a ledge or whether you're going to be stuck. A smoother scheme there would be nice. Otherwise, exploration is a breeze. Finding the hidden nooks and crannies is, as always, great fun.

Blind Enemies: It was good for Metroids to be set on worlds full of dumb monsters and Castlevanias to have dullards as foes. It's less convincing to see Shadow Complex's military-base guards and super-soldiers not recognize our hero when he's standing in the same room, just because he's a little too far away but standing in plain view.

What Should Stay The Same?
An Identity Of Its Own: A couple of moments in the first two hours show what Shadow Complex can do that its predecessors never did. I won't spoil them, but just know that they take advantage of the modern technology being used in the game. And that tech helps this game a lot. This is a Metroid/Castlevania-style game with audio cues, lots of smart use of vocals, and great graphical depth. It's one in which 3D lighting and the hero's flashlight can make hunting for weakened hatches and ducts a more visually interesting endeavor. I did not get far enough into the game to find Shadow Complex's more unconventional gadgets, which will surely distinguish the game even more from others in its genre. Where I'm at, it's a game of machine guns and grenades — a different set of armament than you'd see in a Castlevania, to be sure — but not yet one that allows the action to be consistently clever. The good news is: the game appears to be getting there the further I play.

Pacing: One of Bleszinski's favorite hallmarks of good game design is good pacing. That's evident early as Shadow Complex moves smoothly from one exciting firefight to the discovery of an interesting new environment and then back to an interesting combat scene, punctuated with the discovery of a new gun or the hints of a new hidden power-up to crawl around and find, maybe hidden under an elevator or above the cafeteria full of guards.

Depth-Perception: The game's made in 3D but played in 2D. And that's used to great effect almost every minute of the first two hours. You'll think you've shot the last guard in the room when a door in what should have just been the boring background graphics of the level opens and a phalanx of troops rush in for the kill. It looks great and is fun, particularly because you can shoot into the background. You may only be able to move in 2D, but your gun does 3D. It's Shadow Complex's strongest quality and one that will make it tough to ever return to flatter games in this genre.

Final Thoughts
As I said up top, Shadow Complex could never hope to be as good as the best Metroid and Castlevania games, and I don't think its developers expected it to be. What I've played so far — past an opening a little too in love with the past — shows signs of how this genre can move forward. I haven't even mentioned the XP system which adds a little RPG character growth for every discovered room, every kill — and a multiplier for more if the kills are done creatively.

Shadow Complex is looking like a strong new entry in a style of game that too few developers seem interested in trying to make. Maybe other developers are intimidated. The bravado evident in the well-paced action so far shows that these guys most certainly were not.

One would think that with all the ambitions that Donald Mustard and his team at Epic-owned Chair Entertainment are trying to accomplish with their XBLA love letter to Super Metroid — 3D graphics, a huge world, giant bosses, etc — that they might even have been thinking of multiplayer.

Multiplayer hasn't been done much in Metroid/Castelvania-style games. None of the side-scrolling Metroids have it. Castlevania games on the DS have dabbled with putting co-op in boss rush modes and time attacks.

Mustard loves the idea of trying co-op as a main mechanic in a Metroidvania kind of game. But he said it was an idea that just didn't make sense to prioritize for Shadow Complex. He imagines that, if he could do it, he'd want players to be able to solve complex puzzles, in concert even if they were located on opposite ends of the game's map. In fact, he said that that would be cool if a Metroidvania-style puzzle required players to be spread that far apart.

I suggested that the Shadow Complex developers could prototype the idea and offer it as a downloadable expansion to their game.

Mustard switched into "If we're fortunate to do more games like this"-mode.

If anyone out there wants another experiment in co-op Metroidvania, you better hope he's fortunate.

NOTE: Reader Blue Toast Likes Parenthises notes that this "sounds like Contra" more than it does a Metroidvania. Mustard talked to me about that being a key challenge. Contra can do co-op because it is linear. Making a Metroidvania co-op would have to allow two players to explore and backtrack, requiring much more complex game design. Good luck to anyone who tries it!

Shadow Complex is the third exclusive game from Epic for the Xbox 360, a dramatic stylistic shift from two Gears of Wars. This one's a just-about-modern-day side-scrolling adventure for Xbox Live Arcade primarily designed by Epic's newly-acquired Chair Entertainment, whose design lead, Donald Mustard has distinguished himself as a big ideas man.

The game comes together as the developers may finally be coming into its own. The Chair principals' first game, the ambitious, cosmic Advent Rising, disappointed many and is one of the first installments of a planned trilogy that stalled at one. But Chair's second effort, the underwater combat game Undertow set graphical benchmarks for an XBLA game, which Mustard believes this new game can now surpass.

He predicted to Kotaku during our hands-on session that this will be the biggest XBLA game yet — at least in terms of size.

What Is It?
Shadow Complex unabashedly plays like a 2D Metroid, with its hero traversing 2D levels and backtracking to previously inaccessible areas once he gains more power-ups. Instead of being a lady in a suit of armor who can roll into a ball and shoot monsters, he's a guy with in combat gear who can crouch low if need be and shoot mechs.

What We Saw
Pressed for time, I sat with Mustard as he talked me through an early level in the game. He had me button-mashing to skip his own cutscenes so I could find the hero's pistol, start crawling through ducts, backtrack through alternate routes accessible because I now had the gun that would open my way to them and appreciate that, yes, this game feels like a well-developed child of Mother Brain's favorite series.

How Far Along Is It?
Shadow Complex is set for a summer release, so the game must be close to completion.

What Needs Improvement?
Movement: Metroid games, at least as I remember them, empower the player to perform acrobatic movement fluidly. The hero in Shadow Complex could run well, but he didn't reliably grab ledges or duck when I needed him to. Nothing another fine-tuning of the controls can't fix so that I can focus on movement and exploration, not get frustrated that my guy's not operating as I commanded.

What Should Stay The Same?
The Metroid Stuff: The mini-map for this game is a direct "homage" of the Metroid map, as it creates a colored grid that charts the corridors you've discovered. An optional feature will show the player where to go next on the map, but thankfully that can be turned off for those of us who never needed help to find Kraid or the Screw Attack. The backtracking is looking good. One hopes it is more clever than it is tedious, the knife's edge on which all Metroid games teeter.

The Non-Metroid Stuff: No Metroid side-scroller had this much visual depth, which, thanks to the Unreal Engine or not, allows Shadow Complex's combat to have a faked third dimension. Imagine the hero running from left to right down a street and reaching an intersection. From the distance, over the intersecting road, comes a helicopter attacking our hero. Moving the hero's targeting cursor over that helicopter doesn't just cause our guy to shoot at it, but it turns him so that his gun points toward it and his bullets fire back toward the chopper, as if the battlefield was in 3D. It's a flashy visual trick that adds depth without keeping the game from being classified as a 2D adventure.

Final Thoughts
One hopes that Shadow Complex will eventually be able to boast an identity of its own, but for a first impression, it compares well to its Metroid inspiration. While the game is ultimately being creatively overseen by Epic's Cliff Bleszinski, the fact that Mustard is the driving force — and that the gap is narrowing between his hype for his games and what he and Chair have been delivering — there's reason to anticipate Shadow Complex as an important XBLA release.