Let me just quote a paragraph from the text or two, so you can see why I just saw more and more awesomeness in the X4 and X5 modules:
In encounter 2 of Part 4 (X4:The Master of the Desert Nomads), the adventurers are relaxing with some caravan buddies, elated from an earlier victory over an attack by bandits (by the way, Cook makes good use of all the human "monsters" of B/X...bandits, Normal Men, nomads, dervishes, etc....not just character classes).
If the party remains, they will be the guests of honor at the night's feast. After a thick, syrupy coffee, the merchants will carry in a large platter of camel meat (still on the bone) laid on a bed of rice. Over this will be ladled burning hot grease and melted camel butter until it flows over the side of the tray. Lamshar will then invite the characters to eat. They will be expected to dip their fingers into the tray and pull out balls of meat and rice, dripping with grease. Lamshar and Khel will dine with them, offering the player characters choice bits of camel meat that they have pulled out. After the characters have had their fill (and to only eat a little would be insulting), the other merchants will take their place at the tray. The meal will finish with somewhat green dates.
Now all that text is DM's Eyes Only stuff...this is not boxed text to be read to the players (though both X4 and X5 include some boxed text). Cook creates a whole culture and adventure EXPERIENCE in under 30 pages of text.
Some might think, that with this kind of loving attention to the background material, the adventure would be short on action. No way. He still has room for a full set of wilderness encounters and a 60+ encounter dungeon (the Evil Abbey), as well as including half a dozen new monsters, pregenerated characters, and mini-mass combat rules. And that's JUST X4! X5 is another great 30 pages...this is practically a mini-campaign setting between these two modules.
X4 was published in 1983, the same year Mentzer's Basic set was coming out. X5: Temple of Death was also released in 1983. This is before Mentzer's Expert set or Companion rules hit...
X4 has no shortage of interesting tricks and traps (here come some spoilers folks). For example, back to the previously quoted encounter: all PCs taking part in the feast have to make a save versus poison ("I don't know if it was a piece of under-cooked camel or the green dates, but I'm not feeling so hot..."). Those that FAIL are up all night with indigestion. However, those that are AWAKE get a shot at stopping a sneaky little critter that ransacks the camp that night.
How cool is that? The characters that SUCCEED get to brag about their iron constitutions, but the ones who FAIL get a shot at being heroes later on!
There are a several of these kinds of switcheroos...an ancient Champion of Law that is so obviously the inspiration behind the Scorpion King of The Mummy Returns film (yep, it's now gone bad...)...others friendly NPCs that aren't what they seem (similar to The Jade Empire video game)...plants and double-agents. And am I the only one that sees the Nagpa monsters the direct antecedent of Games Workshop's Lord of Change greater daemon?
Cook also corrects one of the issues I have with X1: The Isle of Dread, though it sets a bit of a bad precedent to later adventure modules. In X1, adventurers can wander around a huge island wilderness for days or weeks without encountering anything but wandering monsters due to encounters being in certain set locations. Players (and the DM) basically have to get lucky (or fudge) if they want the party to run into a particular set piect. In X4 and X5, the wilderness map is set, but the location of the encounters are not...players will experience each encounter when the DM deems the time is right.
Now when I say this is a dangerous precedent I say it comes dangerously close to a linear railroad type adventure...where the only thing that can happen is "players succeed at encounter and move onto next" OR "players fail at encounter and die ending adventure." Adventure path or "story path" in the end all you're doing is living the author's fiction...with widely varying degrees of control (depending on the level of authored NPC involvement). When this happens, it doesn't matter how cool and interesting an adventure...your game play is no longer a collaboration between creative minds, and that's a shame.
Cook avoids this pitfall, and he does so through a number of ways:
1) With a couple exceptions, wilderness encounters need not occur in a particular order. The DM is just ensuring they occur...that's part of the adventure (just like dealing with the throne room or the demi-lich is part of the Tomb of Horrors...there are specific bottle-neck points).
2) Success or failure at a particular encounter does not necessarily derail the adventure. For example, in X5: Temple of Death players don't HAVE to get into the flying ship (flying ship? Yeah, as I said, both these modules are frigging awesome). And in fact, even though it would expedite some things, doing so leads to its own dangers (I shan't elaborate for the benefit of folks that haven't played).
3) In both modules there is a centerpiece dungeon that players will eventually find, and unlike, say other modules, there is nothing linear or pre-scripted in what happens once "on-site." Hell, the dungeons don't even include the boxed text that is present in the wilderness encounters! They are wholely Old School dungeons, complete with Gygaxian ecology and wide open for exploitation by creative adventuring parties.
4) There is no force used upon the PCs through the machinations of NPCs. Players are still calling the shots about what happens in the adventure.
For all these reasons, I don't feel the modules are forced or contrived. Heck, they're even less so than the Desert of Desolation series, with which they sure certain superficial traits. Despite the lower production value, Dave Cook's two-part series may actually blow the Hickman and Weiss masterpiece out of the water. Well...it's hard to say, though as I've had such a love of the I3-5 series for so long.
As far as a B/X adventure? It is easily the best pre-packaged adventure I have ever read for B/X or BECMI. Hands down...it is head-and-shoulders above both B2: Keep on the Borderlands and X1: Isle of Dread. And seeing as how THOSE two made my Top Ten All Time list...well, I might just have to re-do the list.
The thing is, Cook's modules are not designed for kids. Or maybe they are, but they have a very mature, adult sensibility. The power of organized religions? Demons and possession? The need to use wits and stealth over hack/slash/fireball tactics? This ain't no pick-up game for ten year olds, no matter what the Expert set box says.
Of course, we ARE talking Dave Cook here. The designer behind I1:Dwellers of the Forbidden City and A1:Secret of the Slavers Stockade. Snake people and slavers? The guy has a Swords & Sorcery mentality that doesn't quit.
And he brings that S&S style to both X4 and X5. THESE are the potential of the D&D Expert Set...THIS is the kind of mentality I am trying to bring to my Companion set. If Cook had written the sequel to B/X instead of Frank Mentzer, I might have never moved over to AD&D. And, heck, I HAVE made B/X my game/drug of choice after all these years...
Dave Cook is my F'ing hero. Like Gygax and Arneson he should be up on the pedestal of RPG Masters. And, yes, I do realize the total irony with which I write that given his spearheading the design of 2nd edition AD&D leading to the saturation of TSR with sub-mediocre material...but you know, anyone who could take the original mishmash of AD&D and re-organize it has got to be appreciated for design chops regardless of how one views the end result...and I DO appreciate it, even as I loathe the game itself.
Mr. Cook, even as I try to dissuade folks from playing 2nd edition, I will heap praises on your name for your Expert work. And X4 and X5 are shining examples of why B/X is indeed the best version of the game to play. Bravo, sir.
Um...but one, little, tiny issue, Mr. Cook sir. Encounter #2 in the Catacombs? In X4 on page 28? There's no such thing as a "permanent Magic Mouth spell" in B/X D&D...there's no Magic Mouth spell at all.
But one flaw in two modules (for a guy publising in two editions at the same time), is pretty flawless in MY book.