1. Super Meat Boy
There's no part of "brutal and unrelentingly difficult high-speed precision platforming" that I like (adventure and puzzle games are more my speed), but damn if I didn't keep crawling back to Super Meat Boy each time it ripped me shreds.
2. Angry Birds
I know, I know. I can't help but feel like I'm just part of the problem, and I don't want to keep feeding the Rovio machine, but I find the mechanics they added to Angry Birds: Space and Angry Birds: Star Wars to be really compelling.
3. Asura's Wrath
It's not so much the content of the game as the medium and its implications. I loved the game, but I'm also kind of glad it didn't sell super well (at least I don't think it did), because a smash-hit Asura's Wrath would set some terrible, terrible precedents for other companies to mimic. It's a $60 5-ish hour long QTE that (arguably) doesn't even have a full ending without paying another $10 for the hour long DLC. The only thing missing is retailer specific pre-order bonuses. All that being said, Asura's Wrath is still a Goddamn marvel to behold.
I have never once been tempted to use the "hardcore" permadeath modes in games, as I think losing hours of progress because of a single slip-up is more bullshit than "fun." This is significantly more of an issue when a game has randomly generated elements that potentially/frequently hit you with things that are impossible to predict or avoid.
That is almost the exact definition of what NetHack is. But for some reason, I can't stay mad at it.