All roads lead to Xbox Live Arcade. Indie developers strive to have their games featured on it, mid-sized devs attempt to get noticed on it, and huge game publishers release smaller titles on it in between massive, high-budget releases. Over the years it has grown exponentially, with Microsoft becoming more accommodating and allowing bigger and better games to be released at a fraction of the cost they'd be at retail.

With 2012's Summer of Arcade wrapping up, we decided it was a good time to look back and choose which XBLA games over the years have been the best in hopes of helping you sift through the hundreds of titles to find the ones worth grabbing.

At its core, Spelunky is an adventure game that feels like a platformer but borrows its core features from dungeoncrawlers and roguelikes. But from this mishmash of genres comes a startlingly unique game that is as difficult to stop playing as it is, well, just plain-old difficult.

Delving into dark caves and dodging exploding frogs and UFOs can be absurdly hard, and Spelunky made no effort to hold our hand through the experience. But for every dozen times we got knocked into a pit and died, we were given one rewarding, exciting moment of success that makes it all worth it--and, in the end, that's where Spelunky shines.

Geometry Wars: Retro Evolved 2's identity is right in the title: retro, evolved. From its humble beginnings as a pack-in mini-game in Project Gotham Racing 2 to its full release--and subsequent sequel--on XBLA, the series has shown acute awareness of what made retro games fun, and how that enjoyment could be upgraded to the current generation. While the first hammered out the core design, the sequel boasted a healthy number of game modes to keep players coming back again and again. And again. And again. And again and again and again.

Grinding up our Pacifism score or attempting to best our friends in Waves consumed us when the game was released thanks to the use of dynamic leaderboards, which constantly threw our friends' scores in our faces as we played. The "one more game" mindset kept us playing until the sun came up on several occasions, but it was worth it when we'd topple a friend's score... before moving on to the next mode and doing it all again.

Many of the games on this list are a throwback to a simpler age of gaming, 2D love letters to an 8-bit childhood. But none capture the innate joy of that gameplay like Super Meat Boy. Constructed around the concept of sending a little red square through dangerous platforming obstacle courses, SMB’s impeccably retro gameplay is tough but fair. That’s because the insanely challenging levels are supported by pitch-perfect controls and physics.

Each new stage is a contest to be conquered, pushing us to the extreme, but any frustration we may feel is nothing compared to the glory of completing one of the taxing levels. The trial and error makes each platform a carefully timed puzzle that we have to unlock, and as angry as we may be should we come up short of our goal, we know you can’t blame the flawless controls. SMB constantly puts the pressure on the player, but no matter how many headaches it may have caused, we couldn’t stop ourselves from coming back.

With bountiful exploration, intense 2D shooting, and a power-up-hunting Metroid vibe, Shadow Complex has a little bit of everything. That’s not surprising, given the adventure-platformer was developed by Epic Games-owned Chair Entertainment. It’s one of the few games to make us truly feel like we’ve transformed from an average Joe to a super-suited action hero just by playing.

Everyman Jason Flemming loses track of his girlfriend Claire as they’re exploring some mountainous caverns, and stumbles upon a high-tech facility that’s packing nukes. Cue some twin-stick platforming shootouts, a scavenger hunt for hidden items, and some memorable boss fights against colossal robots. The snappy voicework of Nolan North as Jason, mixed with the game’s adventurous sense of discovery and white-knuckle firefights, makes Shadow Complex feel like the sci-fi version of Uncharted. High praise, for such an affordable, accessible action game.

At first, Fez looked like it would be a quirky 2D platformer with an interesting world-shifting gimmick, but that's not at all how it ended up. Sure, it had these elements, but they were just a small piece of a much bigger, much more interesting puzzle. Though platforming is prevalent throughout Fez, it's really a game about delving into ancient tombs, exploring lost worlds, and deciphering alien languages, all to unlock doors that open to reveal more ancient tombs, lost worlds, and alien languages.

Translating these codes wasn't as easy as hitting a bunch of buttons playing some weird minigame--we actually needed to decipher it, with pens, paper and sweat, blood, and tears. Our table was covered with notepads, each filled with random characters and attempts at translation. But once these codes had been cracked, and new doors had been opened, and prizes have been earned, Fez proved itself to be one of the most amazing, rewarding games in years.

Playing Castle Crashers with friends is one of the best couch co-op experiences of the generation. Seriously, it's magnificent. The Behemoth's expertise in the genre led to a side-scrolling beat-em-up that is essentially a long, bloody love letter to 32-bit brawlers, with inspiration drawn from classics like Golden Axe, Streets of Rage, and Battletoads--just to name a few. Carving through enemies as the different knights (and unlockable characters) was an absolute blast, and upgrading and outfitting their weapons had us constantly wanting to begin anew, just to try out a new idea.

Its sense of humor, too, was well-appreciated, with winks and nods to genre's past and remarkably inappropriate, immature gross-out gags. We never thought we'd play a game where a level required us to ride on the backs of deer that were projectile pooping while running away from a monster, but then again, we never really expected to play a game like Castle Crashers.

Besides Mario, Pac-Man might be one of the most recognizable faces in all of gaming. Despite this, there really wasn't a super popular Pac-Man game since Ms. Pac-Man in 1981--and not for lack of trying. Nearly every year saw the release of a new Pac-Man game, but none ever managed to hit critical mass. This trend was finally bucked with Pac-Man Championship Edition, and even more so with its sequel, Pac-Man Championship Edition DX, which updated the classic game's formula to make for an extremely hectic, compelling Pac-Man experience.

Sporting three different modes and a new ghost, DX did for Pac-Man what Geometry Wars did for Asteroids, upgrading the puck-faced protagonist's swagger in a way that made him perfectly at home on the Xbox Live Arcade. Competing with friends to get a high score was incredibly addictive, and kept us--and plenty of others--gaming until there were no more pellets left to collect.

Trials Evolution is many things; it's a racing game, a platformer, and a puzzle game depending on which track we're playing. In some levels we're rewarded for traversing the dirt-covered roads at breakneck speeds, and in others we're asked to climb a nearly completely vertical cliff with nothing but your bike and our rudimentary knowledge of physics and gravity.

The sequel leaves the warehouses of the first game in favor of large, open areas that make it much more visually appealing. This change also has another side-effect: the open-air environments make the excruciatingly difficult later levels easier to bear, as they allowed the developer to create more enjoyable levels without the constraints of the dank buildings. This new location, when mixed with the addition of a level creator and multiplayer, help make Trials Evolution a game that deserves a spot on every gamer's hard drive.

We never forgot how we felt the first time we died in Limbo. We were jumping around, dragging some logs, and exploring the beautiful, creepy monochromatic forest, expecting that the developers wouldn't possibly let anything bad happen to the main character (a small child), and then... BAM. A trap went off, or we fell into a hole, or we got hit by a swinging log, and suddenly the little boy was dead. It's a sobering experience, and set's the tone for the rest of the game.

Limbo is relatively simple, with only a few buttons and mechanics, but what it does with these elements is wonderful. The punishing "trial-and-death" gameplay (as the developers aptly named it) manages to be difficult without being overly punishing, and the way it uses its minimalistic controls to give us all the control we need is stunning. It pulled us in and enveloped us in its dark, dreary setting, and even though it's only a few hours long, Limbo stayed with us for weeks and months after it was completed.

We'd never played anything like Braid when it released in 2008--the game mixed together the platforming and puzzle genres in a way we simply hadn't seen, twisting our brain as we explored the strange, beautiful world. The time-manipulation mechanics made us rethink everything we knew about platformers, and each new tool we gained had us relearning the rules and adapting to the rapidly changing world. We'd stare at the screen, assuming that there was some sort of glitch or mistake that kept us from progressing before suddenly having an "a-ha" moment that would lead to us grinning with self-satisfaction as we passed the hurdle and moved on to the next.

But for as interesting as the puzzles were, it was really the game's tone that earned it a spot in our hearts (and, we suppose, on this list). Sporting themes of regret, memories, and sadness, it used our innocence against us, creating a strange, compelling narrative that stays with us to this day, even if we don't entirely understand what was going on.

For now, at least. The Xbox Live Arcade is constantly being updated with new, awesome games, so be sure to check back from time to time to see what games have been added, and what games have been dethroned.

And if you want more downloadable goodies, check out the best PSN games and if you'd rather some console stuff here's the best Xbox 360 games.