The concept is great. Roleplay cavemen in a prehistory that never was.

The art is thematic and well suited to the game. Some of it is clearly part of the parody element... The Healthy Caveman Class is illustrated with a drawing that is evocative of Richard Simmons in his prime. (Kids, look him up.)

The original layout is nicely done, with a "small press, late 90's to early 2000's" feel, but a few minor issues with not makeing clear section vs subsection header text (subsection header is in the 1st paragraph of the subsection; section header is a line to itself).

The mechanics are the parody element... The rules are playable, they are intelligible, but they seem to be very much OSR-style Early D&D adapted. It is a delightful read, even if one doesn't play it. GIven the mechanics, if one likes Early D&D type mechanics,

The mechanics use 6 attributes, on a 1-18 scale, with 1d6 per attribute, and a second die for your class' prime attribute. Attributes are Strength, Brains, Speed, Banging, Health, Grunting. Classes are Strong, Smart, Fast, Banging, Healthy, and Grunting. There's a 9 point "Attitude" parody of AD&D alignment. Each attribute has several scores, each class has several scores. These interact to provide various resolutions. They are simple, easily understood, but given the 20 statistics, this seems a bit overtaken.

The Big Thematic Rule is that players may only use words off the word list when playing. And not even all of them. There's a small oversight here, in that the characters can only understand those words they know, but since the words known by others will be used, the player has to remember to ignore words they don't know. Still, this restriction makes the game.

Combat is done using d6's, roll low. Attacker gets attack dice from attributes and weapon, loses some for target's defense (from attributes and gear), keeping at least 1 no matter how high the defense, and rolls for hit numbers per die based upon class and level of attacker. Each success is 1 point of damage.

The PDF layout is letter-sized landscape with the original's digest (half-letter) portrait putting two facing pages on one sheet-side... a suboptimal choice. It not only makes printing it into a booklet near impossible, but also makes readability on phones, typical 4-7" e-Ink readers, and small tablets. It's fine on a laptop screen, but any good PDF reader (even before 2004, when I originally got this PDF) could display 2 digest pages at a time and could do booklet printing or 2-up printing.

For many years, I've avoided writing this review... in part, because I love the concept (having written a game about similar subject matter in a far more serious tone), and in part because I didn't want to be harsh on what was clearly meant to be fun. Truth is, I find the concept great, but the rules suboptimal for my range of enjoyed playstyles.

Around 2008, I got the Og: Unearthed edition. It is mechanically almost entirely different... cleaner, simpler... but retains the word list. In all fairness, if one likes Old-School mechanics, this will work; if one wants more focused storygame type simpler mechanics, go for Unearthed, instead.