It's hard to define what "indie" is. If we strictly abide by "any developer that self publishes" (like The Walking Dead's Telltale Games), then billion-dollar companies like Valve qualify. If we say that it's a developer not technically owned by a publisher but is still being bankrolled by one (like Journey's Thatgamecompany), you're including massive studios like Epic Games. Calling it "downloadable" doesn't do anyone any favors, either, because just about every game can be downloaded these days. Instead, to us, indie is more of a “handful of developers in a basement slaving away at code” sort of thing. It’s a freedom that major developers simply don't have--a total control of artistic direction without needing to bow to the bank accounts of corporate overlords.

Indie games have crept into nearly every Game of the Year award category this year, but we still think it’s worth celebrating the genre itself. Today we do just that, putting the spotlight on the indie mindset. Here's a list of the indie games that impressed us the most--and, of course, the winner of GamesRadar's Indie Game of the Year award for 2012.

We’re furious that we weren’t born into an era where space travel was more common. Seriously, in 300 years our great grandchildren will be zipping around the stars, high-fiving aliens and blowing up spaceships for fun. Our only consolation is the existence of games like Faster Than Light, which allow us to teleport our minds into a time where such adventures are possible. They also remind us that we wouldn’t last five minutes in space.

FTL is the Star Trek game we always wanted. It’s a roguelike (see: randomized levels and permanent death) where we’re the captain of our very own customizable spaceship. The upgrade system is complex and fulfilling, and being able to swap out weapons and abilities makes each journey through the stars unique. But it’s really the tactical battles, mixed with the brutal difficulty, that makes FTL so memorable. We’ll never forget the first time we took out a massive ship thanks to a few split-second decisions--or the first time our crew (named after our friends and family) suffocated, burned alive, or got blown apart by space pirates.

Super Metroid with a sword-wielding cat. That’s a starting point for imagining what this awesome XBLA game plays like, for those who have yet to experience it. Combining the Eastern hack-‘n’-slash gameplay of Odin Sphere with a cast of animal-people styled after Western cartoons, it’s an achievement in combat-focused platforming, managing to capture the thrill and satisfaction of a classic Metroid or Castlevania game with the low budget of an indie developer.

Everything you encounter in Elysian Tail feels just right: The combat is phenomenal, the characters are endearing, and the vast world is ripe for secret-seeking exploration. Wielding the sturdy Blade of Ahrah as samurai cat Dust, you’ll get a rush of adrenaline every time a pack of enemies shows up--because that means it’s time to slice and dice them with a bevy of flashy combos and magic attacks. It’s like a mash-up of your favorite childhood storybook and the battles of the 16-bit era, easily making it one of the year’s best.

Most "ninja" games have you running around in cool clothes and lopping off the heads of bad guys en masse. But Mark of the Ninja might just be the best actual ninja game we've ever played. Not that we really know what it's like to be one--but we'd wager it involved a lot more sneaking than head-on skirmishes.

Planning your every move in this 2D sidescroller is essential, as it prioritizes stealth over being a gung-ho hero. You'll have to operate from the shadows while dodging traps and taking down bad guys before they ever had a chance to know you were there. And, should you fail, your score will suffer, resulting in great shame for your clan. Mark of the Ninja is a lesson in masterful, minimalist stealth design--and it's one of those addictingly difficult games that will send you spiraling toward obsession.

Some might argue that the pixelated puzzle platformer approach to indie game design is the safest path to take, but Fez is more than its pixelated parts let on. While it starts off as a funny, cutesy retro homage with a neat, world-spinning gimmick, it quickly evolves into something grander. Something more impressive. Before long, your eyes will be glazed over, your brains will be leaking out of your ears, and you’ll be neck deep in one of the most enigmatic games released in a long time.

Fez’s brilliance is in its depth. Its simple platforming is fun, but it eventually takes a backseat to delving tombs and deciphering codes. Cracking said codes will unlock new in-game languages, leading to new areas that reward you with more cubes to collect and even more puzzles to solve. The sense of satisfaction after uncovering one of the encoded languages is immense, and the feeling of reward is incredible. It’s not a game for everyone, but if it hooks you, good luck escaping with your sanity.

Legend of Grimrock’s presentation made ancient gameplay feel new again, introducing a new generation of adventurers to the wonders of first-person, tile-based dungeon crawling circa early ‘90s PCs. Instead of tasking you with mundane fetch quests, a cliché fight against evil, or blabbermouth party members, Grimrock takes a simpler approach: Your four-creature group is trapped in a labyrinthine prison-tower, and the only way out is down. Rather than bash you over the head with its story like one of its many monsters, the game lets the arcane mysteries of its sinister dungeon unfold through ethereal dialogue and hidden messages.

The atmosphere really drives home the feeling of being trapped in a dank, claustrophobic stone prison--which is absolutely a good thing, in a gaming landscape filled with bloom lighting abuse and heroes that look like action figures. And taking on the mythical creatures in Grimrock actually feels like a test of your resolve, instead of a means of accruing XP. It’s terrifying when a raptor gets the jump on you while you’re resting, and you’ll bellow a victory shout after downing your first Tunnel Ogre.

A lot of games these days, indie and otherwise, make a big song and dance about bringing back the spirit of "retro" games. Most of them do so simply by being harder than a concrete rhino, irrespective of any other design sensibilities.

Mutant Mudds, however, is the real deal. It’s basically a NES game, polished up to within an inch of its life. Other than an endlessly coo-worthy 3D depth of field effect, there’s barely a concession made to anything created after 1987. The result? An utterly pure platforming design, lean of frills and tighter than drum-skin. It’s demanding, requiring nothing less than utter discipline, precise timing, and a keen eye for pixel-perfect spatial navigation. But it’s also bright, breezy, funny, and endlessly likeable. And the DLC is centred around a granny with a jetpack. Enough said.

Far more than the simple tribute to old-school GTA that it might first appear to be, Hotline Miami is smarter, sharper, and more exhilarating than Albert Einstein on a knifing spree. Essentially an ultra-tactical, high-speed stealth game, Hotline’s pacing and brutally precise demands are less a case of “blink and you’ll miss it,” and more a case of “blink and you’re almost guaranteed to find your innards spread over a very wide area.”

It’s a game that looks effortless--mindless, even--in successful execution, but in which a single level can take more than an hour of second-to-second pre-planning to complete. Not that you’ll mind. That feverish loop of plotting, failing, restarting, and eventually succeeding is one of the most satisfying and compulsive experiences provided by a game all year.

While Faster Than Light, Hotline Miami, and Legend of Grimrock reminded us of the enjoyment in punishing difficulty, and Dust: An Elysian Tale, Mutant Mudds, and Mark of the Ninja presented us with some of the sleekest 2D gameplay we’ve seen in a long while, their successes were in reminding us what we love about gaming. Fez, on the other hand, gave us something wholly new to love, which is why we’ve decided to award it our Indie Game of the Year award for 2012.

Its adorable graphics and retro style might have been what brought us in originally, but the cryptography-style code breaking is what kept us interested for dozens of hours. The world is whimsical and imaginative, and the game is so multifaceted, so imaginative, and so complex that it’s hard not to become obsessed.

Whether or not you agree with our choices, there’s no denying that 2012 has been a monumental year for indie games. Small developers all over the world came out swinging, aiming to prove that they could do with a miniscule budget what many thought would be impossible. And by god, they did it, and they did it with style.

Be sure to vote on which game you think was the best from the choices below (or add your own), and we’ll include it as a Community Choice award in next week’s Platinum Chalices!

And if you're looking for more awesome games to play, check out the best shooters of 2012 and the most anticipated games of 2013.