Your expectations> Fuck 'em. They don't apply here. Sure, this game starts out innocently enough, with simple Megaman gameplay and graphics strangely reminiscent of Cave Story. As derivative as it is, you'll probably appreciate the polish to it and truck through the unimaginative fluff that this game is. Then, you'll encounter a seemingly typical boss fight; after which things get interesting. Care to fathom the depths of this critique after you play this thing?
Cool stuff. Fathom completely inverts the archaic conventions you assumed from your first few minutes of playing the title. Where to begin?
You start out in the all-too familiar territory of a Megaman ripoff, completely comfortable with your vocabulary, play controls, and objective. Jump and shoot, and maybe pick up some useless trinkets all the while. If you're over seven you won't be surprised by your enemy's attack patterns, and you can easily maneuver through the level.
You eventually stumble upon the enormous boss character, you already know the drill. What you don't know, however, is how to react to falling through one of the chasms in this fight. Your usual ludic response is "fuck, I have to redo this again" or "fuck, game over." Instead, the game provides its first inversion. Like your protagonist, you have no clue of your alien surroundings. You're plopped into the fathoms (nudge nudge) of this body of water and then naturally you fathom (wink wink) your predicament. The controls are atypical of your usual game, and your violent weapon is now nothing more than a propulsion device. It's also worthy of note that when you reach the inner depths that your flashlight is faced in front of you, the opposite direction of your movement. This makes your character a lot more methodical than when he was running and gunning through the first section.
As mentioned above, your weapon is a movement tool, and instead of enemies you encounter various pacifistic fish (which you initially have no clue how to use). You wander around this environment, and try to find your next course of action. In time you'll pick up an object, unsure of what it does. After enough tinkering, you might notice that the fish are guiding you towards something... if you're still mystified, just float through the depths and you'll find your goal. I could go into the second section after this, but I'll let you discover that on your own.
This game flips a huge middle finger against stale and conventional gameplay. Sorta like You Have To Burn The Rope, you're given a very simple task that's exasperated by your expectations of industry games. You're no longer a macho dude blowing shit up, the focal point of a universe; you're more of a passive, floating speck of dirt fluttering through an immense ocean. Slowly learning how to navigate and overcome your surroundings feels a lot more sincere than the mindless running and gunning of the original gameplay. You appear to be part of something grander, and subsequently you feel more insignificant, when you play Fathom. Humility is typically a problem with game protagonist and gamers, but when you give that bravado up you get something more special.
P.S. I may also add that the Cave Story-ish graphics that accompany your initial moments might be a tongue-in-cheek way of saying that we indie developers and gamers should strive for more procedural and cerebral experiences, rather than rehash (however awesomely) old ideas. Of course, I loved Cave Story and have much respect for Pixel. Just saying.