From the draft thus far, it's really close to how OD&D ought to be, with Greyhawk included. A few anomalies – like percentile Strength and weapon versus AC – that I'm not fond of go away in this revision; I can't say that I mind. All the things that Gonnerman had done away with in BFRPG, like descending AC and alignment, are all there in the core section. The spells that are there work like in OD&D, such as Charm Person, which lacks Greyhawk's convoluted saving throw scheme (also familiar for AD&D players).
Where Delving Deeper is a clone which is obsessed with getting into the gritty details of the original OD&D booklets, and where Swords & Wizardry is a nice, light game that is more in the "ballpark" of OD&D, Iron Falcon is looking to be a tight, feature-complete clone of OD&D as it was played in the early days. As Chris says on the BFRPG forum thread:
Greyhawk is the first published book that shows the game in a recognizable form; it's how Gary's own game worked, as much as he was able to publish it. I recall having heard that the game was undergoing heavy development, changing all the time, so Greyhawk can be little more than a snapshot... but it's the only snapshot we have.From what I've seen, and from what Chris has put forward thus far, it's an extremely worthy effort to put together rules that would have been recognizable in 1975 as the D&D rules. If it continues on these lines, I could seriously see switching to Iron Falcon as my go-to rule set for OD&D type games. It has everything I would want from a clone. (Well, everything except robots. But that can be fixed.)