1. SpaceChem; It's a fresh experience, a mental gymnastics puzzle game with real bite. The puzzles are objectively difficult to solve, tiny solution spaces speckled through a vast problem space, but the solutions aren't singular. There are, in reality, many ways of solving each one, and any particular solution is rated on three scales (number of cycles, number of elements or commands, and number of plants), along with the distribution of results that other players have scored in each. This brilliant little bit of feedback pushes the perfectionist in me to keep going back and refining each solution, hunting for a better mousetrap, wracking my brain to figure out how those 2% of players managed to get this ozone manufactured in twenty fewer cycles than my solution. So addictive, such a time sink, and with the patched-in tools for publishing your own puzzles, almost infinitely expandable from its core toolset. Maybe it's the engineer in me: Nothing in gaming has been more satisfying than watching my little machines pump out four different chemicals and ship them to the correct containers, the fruit of an hour's labor.
2. Portal 2; Valve now has three franchises which hinge on one conceit: You are a rat in a peculiarly structured maze, and your only chance to survive is to attempt an escape. Half Life's Gordon Freeman runs a gauntlet of alien predators and paramilitary thugs to survive an extraterrestrial invasion. The Survivors in Left 4 Dead struggle to stay alive for another sunrise to run for sanctuary in the midst of the zombie apocalypse. In the Portal games Chell is literally run through laboratory mazes. The artifice is bare, visible to all. But what a fantastic maze it is! And what deliciously naive malefactors, comically oblivious to how silly their motivations are! And how perfect that, in the end, you finally see the unobstructed night sky and think, aha... Escape!
3. Ghost Trick: Phantom Detective; What a surprise, another puzzle game. It's been an odd year. The humble DS has birthed a few improbable successes, games that succeed because of (not in spite of) the platform's quirks and extreme limitations. Ghost Trick is the latest, and maybe the last, of these... the baton for this sort of thing is being passed on to new handhelds, perhaps phones with their small screens and invisible control options. Screenshots of this game look simply terrible. The gameplay sounds thin, the premise silly. Put it in action, though, and this pig can dance and sing... The stills can't convey the winsome animation. The gameplay really works on the touch screen of the DS (or iOS devices, I presume), and while the puzzles aren't at all difficult they're fun in an "escape the locked room" kinda way. And the story, while definitely silly, is endearing in the talky, mushy, earnest way of other Shu Takami games... it shares that pleasing TV dramedy quality of the better Phoenix Wright titles.
4. Xenoblade Chronicles; A great, grand RPG, it's a wealth of riches in a genre that's become increasingly stingy, and on a console that has never before boasted such a big game. It's big in many senses. The story is loooong, packed with twists and turns (and told with hours and hours of voice acting). The cast list is likewise long. The gameplay system is deep, rewiring Final Fantasy 12's real-time combat system with clever new "foresight" elements. The options for character and party customization are extensive. So far, so much a jRPG, but the developers weren't satisfied with one genre's idea of big design. They pulled in ideas clearly more common in western RPGs: a crafting system that can be used to upgrade equipment, mounds and mounds of optional quests complete with hidden quest lines and (unfortunately) gathering quests in the type of "kill X of Y to get Z", fast travel to most previously-visited places, always visible enemies, and so forth. It even steps in territory normally trodden by MMORPGs and Monster Hunter sorts, with "mining" veins and dynamic day-night and weather cycles. Even the game's environments seem crafted to impress with a sense of scale, with a titanic creature standing in malevolent vigil against the skyline. None of these elements are new, of course, and someone can point out games that do any of these, but there's no denying that it's been hard to find a game daring to be so grand in every direction, and doing it all so flawlessly, even on such humble hardware. Of the several big-scale RPGs released this year this is my choice for a memorable, rewarding gameplay experience.
5. Deus Ex: Human Revolution; I've never played a Deus Ex game previously, and I think that worked in my favor here. The theme of the game is Doubt. In a gameplay sense this is promoted by giving the player many options but little feedback on which is the correct path. Consequences are real (at least in the view of completionists)... my Adam was stealthy and quiet but no hacker, and I was painfully aware that my decision to stay relatively computer-illiterate prevented me from seeing some of the game content protected behind firewalls that would fry my cyberbrain like a wet toaster. I'm also a sucker for the setting- I don't believe cyberpunk in a videogame has ever been better done. Someday I'll get around to playing the Blade Runner adventure game and, perhaps, prove myself wrong.