Well, I got mine about two weeks ago and have spent my spare minutes reading through it to get myself an opinion. For whatever my opinion is worth, here it is.
I'll admit right up front that I've not had the chance to play the game, and I might be entirely wrong about it, but then again, what's the internet for except for strongly held, mostly baseless opinion sharing anyway?
First impressions: The first thought I had when I pulled the book out of the mailing envelope (immediately after being annoyed with the postal worker who folded the book double in order to fit it in the mailbox despite the words "DO NOT BEND" in bold red lettering on the front, and immediately before the panicked moment of flapping my hands uselessly as I was attacked by half a dozen red ants swarming out of the thing) was "this is just too thick to be "basic."" Weighing in somewhere around 200 pages, this is well beyond what can reasonably be called an introductory book to a game. If anything, it gives the impression that the basic moniker is there simply to hearken back to D&D Basic, shamelessly so.
James was right, this isn't a particularly Old School product, at least not in the sense that Old School has come to be defined by the OSR (or whatever we're calling it nowadays).
Presentation and Physical Stuff: In terms of physical quality, this book earns high marks. The binding is sturdy,as are the cover and the pages themselves. High quality materials throughout and no obvious or glaring printing errors that can be a major drawback to any product.
Speaking of the cover, yes, it's an Erol Otus print, and a damn fine one. Evocative and just slightly comedic. That creature on the front (a variant of the hydra if anybody cares) is just weird enough to catch your attention and make you wonder, and just vicious enough (he's eating the fighter's leg for crying out loud!) to give you a hint about the tone of things within.
The art throughout is quite nice, though not entirely inspiring. It's certainly worlds better than the current "art" plastered all over more "modern" RPG's, that's for sure, but it just doesn't grab me. Don't get me wrong, I like the woodcuttings just as much as the next guy, but it's just not all there yet, and too much of it looks to be recycled from Hackmaster 4th for my tastes.
Other than issues of personal taste, there are no complaints in this department. The book, as a book in itself, is of excellent quality, and even after being folded in half for 18 hours in the mailbox, the entire thing recovered in less than 2 hours and now you'd never be able to tell. This book was obviously built for extended and hard use.
Content: If you didn't care for Hackmaster 4 as a game itself, then you probably won't like Hackmaster Basic (and presumably HMA since it's purported by the authors to be the same thing, except more-so). If you looked at Hackmaster as a source for clipping out interesting rules variations, then you probably won't like Hackmaster Basic very much as the new stuff here won't be of too much use to your AD&D type game: the differences are just too broad for easy portability.
Whereas the original Hackmaster could reasonably be called AD&D with a whole lot of house rules and attitude thrown in, HackMaster basic is a new animal. It's certainly heavily informed by the D&D Basic model: the four classes are, of course, fighter, thief, mage, and cleric and they've got the basic races down to human, elf, dwarf, and halfling, and largely they mean the same things. Mages still cast magic spells, clerics still channel the powers of their deities and often turn or command undead, fighters are really good at hitting things, etc. The rules, however, are not basic as we understood them back then.
Each race in Basic has its own little chart that helps you understand the gist of the rules governing it ranging from attribute modifiers (and there are several, not just the +1/-1 from the days of AD&D) to what talents can be purchased at discounted rates and the number of building points needed to purchase your way into each particular class. One of the greatest advantages to being a demi-human is that you can purchase your way into certain classes for a substantial discount (say, 20 points as opposed to an average 30) and if one follows on with typecasting, demi-humans will certainly excell at certain types of things. Dwarves, for example, make excellent fighters if but for a slightly lower movement rate and a reach penalty, both of which can play significant roles later on. Elves make good wizards, halfings thieves, and humans fall into their jack-of-all-trades role again. Of course, level limits are a thing of the past as, in Dave Kenzer's own words, "research shows that most gamers tend to be frickin' pussies . . ." and the increased cost to enter the class in the first place seems at first glance to help balance that out in the short and middle game. Long term, though, I guess that things would tend to even out on some level.
Attributes are rolled for by the standard 3d6 along with their percentile fractional values (typically used in the original as further gradations between attribute points and as stepping stones between advancing attributes between levels) and seemingly the same here. In terms of a basic game where attribute advancement is left out, I don't see the need for the fractional ability scores. It muddies the waters for those who don't know what's coming up. Though I can see the desire to leave as much from the eventual "final form" of HMA the same as possible rather than following TSR's model of slicing the game into two different lines.
Higher attribute scores are, as in AD&D, important to a character as they govern all sorts of things as how many hit points characters get, how hard they hit in combat, how quickly they can act, etc. Those who don't like a strong reliance on ability scores will not be overtly pleased here I think.
Up until this point, there's little difference between AD&D and HMB in concept. They both follow along the same models. But it's when we get to the nitty gritty of the rules that the paths diverge. In concept, the rules are very simple. In execution, though, I see a whole lot of individual nightmares.
Skills operate on a system very similar to the Aces & Eights model, though they start at 0% for untrained and ascend towards 100% for masters. There are some skills, known appropriately as universal skills, are things that pretty much everybody has some facility with. Things like Hide, Sneak, Climb, etc. fall into this category. Other skills, like animal handling, riding, and academic type skills fall into the category where, without training, you have no real hope of using the skill. You gain and advance skills by spending build points. Not a bad arrangement, though there are still more skills here than I think are helpful and, of course, I'm still a strong believer in the proficiency model of AD&D 2e. Overall, I think this skill system is an improvement over HM4 provided that the skills don't expand into idiocy as the original game's did and provided we don't slather on layers of complication that add little to the satisfactory feeling of the game.
Clerics deserve to be singled out since, it seems, Kenzer & Co. have finally done what so many have wanted before and created a separate class for each deity. A Cleric of the True is not the same as a Cleric of the Harvester, is not the same as a Cleric of the Riftmaster. Great! Except that they still look very similar except for a few paltry, desultory differences. Maybe I'm judging that harshly, though. It's nice to see at least some service paid to the concept.
Combat. Combat is . . . well . . . it follows hot on the heels of the successful model of Aces & Eights. Somebody made the very astute observation that, realistically speaking, combat doesn't happen in nice, orderly rounds, but in real time. So Hackmaster Basic operates on the "count up" system instead. The GM begins combat by calling out each second as it passes (i.e., "1: the orcs start their charge while you stand surprised, 2: they continue to charge . . ."). Once your initiative arrives (the point at which you realize combat has begun and aren't standing there gaping like a landed fish) you are free to act, though each particular action takes a certain amount of time. A long sword, for example, takes 12 seconds to "reset" after its first attack, so unless something happens in between, you can expect to be able to attack once every 12 seconds with your sword.
Movement operates on a separate, parallel track to hacking, so you can, each second, move a distance equal to your walking, jogging, running, or sprinting speed every second independent of what your sword arm is doing at the time. Of course, moving out of melee with a foe, assuming he stands there like an idiot, can lead to a counter "reset" for your weapon, but again, nothing in execution is simple as it is on paper. I suppose that's going to be the calling card of this game, in the end.
Trading blows is accomplished by an, in my opinion, excellent model: opposed rolls adding modifiers, high roll wins. I think that, in basic premise, that's a GREAT way of doing things and I've often pondered what the effect of turning AC into a modifier to a d20 roll would result in at the table. However, in the end, the simple makes way for a host of complications, many in the interest of realism. For example, not carrying a shield gives you a flat -4 to your defense rolls as, of course, these are very important items in medieval combat. Why, you might ask, do you suffer a penalty for not carrying a shield rather than simply get a bonus for using one? Well, that's because there's another complication later on for what happens when your oponent misses you while you're using a shield: you still can suffer damage from this as the book points out because your arm is, after all, right on the other side. There are, as well, different types of dice to roll for defense based on if you are caught unaware, or are helpless, or are being attacked from behind. Initiative dice are the same, a different one for each circumstance, though there is, as in most rules, a standard. Maybe its my pessimism, but I see the standard being excepted too often to be of much use, really. In the end, here, I'm left wondering whether I really want a realistic system as opposed to a comfortably abstracted system that blends into the background and is all but completely invisible at table.
For all that, though, combat itself is explained rather well, including via a nice little comic strip example. It makes me think that, given a little patience and practice, I could GM it successfully and make it fun, which is, in the end, the point of it all. If you're a fan of the comics, it'll make you chuckle and you'll probably appreciate it. If not, you'll probably be a little disheartened that such a bit of crucial info is dumped into a comic book format that you have to slog through.
Despite my overall negative tone above, I do think that the combat system is very interesting and worth a look through even if you don't plan on playing this particular system. It looks like it'll prove to be a gritty, violent, and brutal affair rather than the high fantasy swashbuckling that D&D can often fall prey to. Shields break with alarming regularity, wounds do not heal overnight, and those large pointy objects that were a minor annoyance to AD&D figher characters can be exceptionally dangerous with the risk of penetration and critical hits. Even when armor is absorbing damage, we're still talking big, satisfying numbers here even at first level. A three foot blade in the gullet is about as debilitating in Hackmaster Basic as it would be in real life, and that's a good thing.
Honor remains as yet another fiddly bit. Spellcasting has morphed into a strange, almost Arduinian combination of the Vancian slot system and a spell point system (I heartily encourage you to check out the book if only for that).
The monster selection is quite nice, though sparse considering what fit into the original Baisc books. Something on the order of 75 monsters including several undead like vampires, ghouls/ghasts, and wights. Dragons are conspicuous in their absence, though rumor has it that they are going to make an appearance in one of the KODT issues coming up. Undead no longer drain experience, but ability scores semi-permanently (there's a moderate chance that you can recover, but it's by no means a sure thing as it was in 3.x). Poison is a rather nasty affair, though not always of the save or die variety. All in all, an excellent selection of monsters to start the game with including a few classic Hackmaster creatures like the Sturm Wolf.
There are at least two sections of the book that I see as superfluous and as taking up more space than they are entitled to. First, there's a "Quick Start" characters section that you can download on the Kenzer & Co. website for free now to look over as a PDF. In my view, this is a basic game and it sure as hell shouldn't need a quick start setup. If anything, they should have included four or so pre-generated characters for that purpose rather than taking up half a dozen pages with marginally useful information.
The second was the dice rolling section. Yes, it's well written and very fun to read, and a lot of it needed to be said as so much "dice ettiquate" has been forgotten and ignored over the years, but really, it's too big for what it is and it should have been dropped in favor of streamlining the rest of the book, or for at least adding more monsters.
Overall: Despite my general negative tone above, I do think that Hackmaster Basic is an excellent looking game based on a read through and no practical experience with it. It garners 4 out of 5 stars from my questionable perspective, loosing points only because it's not really basic at all and the amount of fiddelyness is too much for my taste. It's apparant that Kenzer & Co's definition of Old School is significantly different than Matt Finche's.
Buy it if you enjoy reading a well written game that has a good sense of humor about itself and the entire hobby, but is much toned down since the last PHB.
Buy it if you love Hackmaster in general and would buy just about anything Kenzer published on principle.
Don't buy it if you're looking for an old school experience as it's defined currently by the Old School Revolution.
Don't buy it if you're looking for a basic, simple, and quickly grasped game.
A Note on Hackmaster and Kalamar: It should be noted that Hackmaster Basic is the first new product in the line that will specifically support the Kingdoms of Kalamar setting. As noted above, the Cleric class has been specifically subdivided into a unique class for each of Kalamar's many deities, though only a few make an appearance in Basic.
This connection is definately noticable, but hardly so overt that one couldn't adapt the game to another setting with relative ease.