Olde House Rules (publisher)
I don't recall how I came across this but I love zine-like publications and OSR rules takes. I think I might have first seen a post on Google+ about this game. The PDF is $3.49 at RPGnow.com, which I think is a fair price. The cover played into my choice, as it usually does. I like everything about the cover except putting the subtitle and authors names in that blackletter font. I think the title would stand out better with something more understated below.
Overall this is an interesting take on making a diceless game and keeping a very old school feel. I'm going to jump right to the punch and "spoil it" for you. There are two key mechanics, as I see it: talents and fights.
As a character you have talents which tell you what kinds of things you can do. The GM can complicate those things or put dangers in their way, but when it gets down to it you can do the thing, whatever it is. A character with the talent "Jailor" can pick locks and disarm traps; a character with "Inspired" can detect supernatural evil within 30'. And every character gets three of those. Wizards are a little different, but it's not worth going into here other than to say the system assumes a fairly low magic setting.
Fights are another matter. Talents don't come into play. You have 10 wounds and it's mostly a matter of how long you want to stick out a fight and how much damage you are willing to take. Weaker opponents take less time to kill off and do less overall damage; the reverse is obviously true as well. Damage is divided up however the party likes. So a group of four characters fighting a weak force might fight for three rounds and take five wounds. (You take one wound per round minimum, and then some monsters have damage bonuses.) Only the GM knows how long it will take and what the damage bonus is, so at the end of each round you take your licks (decide which characters soak up the wounds) and think about whether it would be smarter to run away.
That's fairly neat. At first I wanted to sneer at it, but honestly, this is how most D&D fights work anyway. Initiative and the swingy nature of dice make a difference, of course, but in the long run fights pretty much just feel like a question of sticking it out and hoping the other guys go down before you do. I'm not sure that's a good thing, but if it's a bad thing at least this way of adjudicating it will be more cinematic. (Fighting is mostly about description since there's no dice.)
[Edit. I should add that you can 'use up' your armor to shrug off a mortal wound. You can repair the armor later. Also, you can spend experience points to make a 'save.' That's a pretty cool idea.]
Be warned that this book also puts a LOT of power into the GM's hands. Maybe this is just my impression, but I feel like I would be trying to convince the GM to let me just use one of my talents and they would feel it was their job to not just let it happen without some kind of complication.
The book is well-written, clear and with a good flow of information, though I found it to be slightly judgmental of heavier rules and high magic systems in the first few pages. I would prefer to be told what's great about this system without the author taking cheap shots at other systems. But this bias quickly works itself out and isn't anything you haven't heard before.
It is also laid out well for a zine-like publication and uses public domain art to good effect, but I have to ding it pretty hard on its choice of font. Generally, I kind of like old typewriter fonts, but in a misguided effort to look vintage (?), the courier-like font of Diceless Dungeons has a double-strike effect that makes the text a little blurry looking and harder to track with the eyes. Not only is it not a good choice and a mild barrier to readers, but the public domain art doesn't have these ink-ghosts, so it doesn't even really make sense in terms of creating a kind of atmosphere for the book.
Sadly I think this book falls into the same hole that a lot of OSR clones does for me personally. I would gladly play it, but I'm not going to be the one to bring it to the table. Unless there's a group around me that is really hot on trying this thing out, I'll likely never get the chance to experience it.
[Edit! It just occurred to me that this system might make a lot of sense for Play-by-Post.]