The Game I Like

ODD Clones
The original White Box was published in 1974 and is aimed at wargamers as an audience. Shortly after publication word of this new game spread outside the wargames hobby and people who had never played a wargame became interested in the three Little Brown Books. The folks at TSR soon recognized that an opportunity existed for them to introduce their new game to folks outside the established hobby and in 1977 published the first Basic Set as a way to bring new players into adventure role-playing. The result was the 1977 Holmes Basic edition (edited by J. Eric Holmes) which is to this day among my favorite role-play volumes.
The Old School Renaissance (OSR) has given rise to many new clones, retro rule sets, simulacra and rules inspired by the Original Role-Playing Game (and older games in general). Delving Deeper (DD) is among my favorites for a number of reasons. First, it adheres fairly close to the original three Little Brown Books. The Thief Class is present, but is optional. DD retains the elf race as one alternating between the Fighting Man and Magic User class - just like I read it in those three LBBs. It uses a five "saving throw" classification system, three alignments and descending armor class (ascending is an option) - the mechanics for each are only slightly altered from the original. It also includes rules for jousting similar to those found in Chainmail. The names of some of the classic monsters are changed as DD uses the OGL and SRD. The author, Simon J. Bull, makes certain interpretations and adds his own comments, explanations and original content to the game, making it more beginner friendly perhaps than the original and an interesting alternative for an experienced White Box player.

Iron Falcon by Chris Gonnerman is another OSR retro-clone which adheres closely to the original three LBBs. Mr. Gonnerman also draws from Supplement I, Greyhawk (Iron Falcon - note the similarity) as many consider the three LBBs together with Supplement I to be a more complete game than the three LBBs by themselves. I disagree somewhat however as I am not a fan of the Thief class, variable hit dice for the classes, or variable weapon damage (the two work better together). The half-elf race seems an odd inclusion in the original Greyhawk as various sources have indicated Mr. Gygax, whose campaign was named Greyhawk, was opposed to half races. (The half-elf concept seems to have been borrowed from the work of J.R.R. Tolkien?)
Iron Falcon, Delving Deeper and the other OSR systems drawing heavily from the original TSR games add their own interpretive content. In the old days we might call it "house ruling". Their unique take on a well known original is what gives these publications value to me personally. I find there are many good ideas in these OSR "labors of love" and I frequently borrow from them for my own White Box games. They also serve the function of allowing an affordable option (many have free digital versions) for folks who are interested in the out-of-print games and also offer a vehicle for publishers of new game aid material (including adventure modules) without violating copyright.
Swords & Wizardry and the many variants that have been published using it as a basis are generally of interest to me as well. The one thing Matt Finch does with his Swords & Wizardry (S&W) game which I disagree with is his reliance on the single saving throw value. I rather prefer the original Saving Throw Matrix (which is included as an option in the "White Box" version of S&W) as it adds more variety to the character class and gives the referee more flexibility when calling for a saving throw. Multiple saving throw values are more character sheet data to keep track of and they vary only slightly between the classes, but the White Box character sheet is still a pretty simple affair. S&W has had an enormous impact on the hobby and serves as the basis for a large body of game aids, adventure modules and other OSR simulacra. (Its value to the hobby is well established.)