Is that even a computer game genre? Platformers where the game utterly hates you, does not provide save states or extra lives, procedurally generates the levels and - in the case of Spelunky - has extensive interaction with the level environment. Well, if there isn't, I'm making it up now.
Spelunky (downloadable) by Derek Yu takes you, in the guise of a chibi Indiana Jones, through four different "worlds" with randomly generated levels. And it's deadly. You get a life meter with three hearts, but that's not worth much once you realize that giant boulders, bombs and certain monsters instakill you anyway. And then you restart from the beginning of the game, because Spelunky hates you.
Yet it's still fun, because the levels are new in every playthrough (though with familiar building blocks after the twentieth playthrough or so) and a game takes about 10 minutes so you aren't actually losing that much progress when you die. Much like Rogue, except as a platformer.
It also borrows the concept that everything is useful (more prominent in Nethack than Rogue), so eventually you will be picking rocks and skulls off the ground to trigger motion-sensitive arrow traps, and then tossing the arrows at enemies to kill them. More evil players do that with human corpses instead...
Tower Of Greed (flash game) isn't nearly as complex as Spelunky, but it still has a certain roguelike appeal. You jump up a downwards-scrolling level like in all those other downwards-scrollers. The twist is that you are supposed to gather gems along the way, and then you can leave the tower (through doors along the tower) when you feel you have enough gems. If you die before leaving the tower, you don't get recorded in the highscore table, and (more painfully) your achievments aren't saved. You have to quit willingly to have the game count.
Of course, there are "achievements" for both how many floors you can survive and for how many gems you gather - I haven't quite gotten to 100 floors yet.
Simplistic, yes, but the controls are close to perfect (unlike the feeling of steering a paraplegic slug I get from many other scrolldown platformers) and the levels are somewhat procedurally generated (though with big building blocks, so you end up learning how to pass certain floor designs anyway).
And much like Spelunky, a game takes about 5 minutes, so failure doesn't lose you that much game time. This... has gotten me hooked in a way no other game in this genre has before. Good job.
I'm keeping an eye out for other games in this genre.