So I was interested in looking at the Original Flatland RPG and read through it on Christmas Day. By the way, I think that the word Original is used to indicate that the rules were designed for the game, since there have been adaptations to use other rule sets for Flatland.
Mechanically, the Flatland RPG uses a traditional structure with a game master and fairly simple system. Characters have a mind stat and a body stat, largely determined number of sides. Throw in some disadvantages and advantages and some skills and you're done. Resolution is done by rolling two dice and consulting a chart.
But no one is getting on board a Flatland game for the mechanics. You buy your ticket for the setting.
A lot of the setting development comes from the sample adventures and adventure seeds. Which, tragically, ended up being the least satisfying part of the book for me. Because they were filled references to lots of pop culture. The Sharpe novels, Scarface, High Lander and Lovecraft were all prominent.
My problem is that, as simple a concept as Flatland is, it is still a dinstinct and profoundly alien setting. Adding elements from other works doesn't seem to do the setting justice, as well as not really exploring the setting.
The other big chunk of setting development are the appendixes which discuss the science of Flatland. Now that, on the other hand, is what I was hoping for and was a lot of fun to read. I really got into that and everything I felt like I wasn't getting in the adventures I got there.
The book also includes the rules for a light war game/abstract strategy game that simulates warfare in Flatland, a bibliography of inspirations and the entire original novel, since it public domain. I doubt I'll try the war game but it's fun to include it. And it's not like I need another copy of the novel but it is nice to have included it, which also doubles the size of the book.
I wasn't surprised to The Planiverse in the bibliography. It's the most important scientific examination of a two-dimensional world, as well as the inspiration for Alak, a one-dimensional Go variant I like to play. Really got to read it one of these days. I was surprised and delighted to see The Fantastic Umbrella, an obscure fantasy novel that has the characters visit Flatland in one chapter.
The Original Flatland RPG isn't the definitive RPG for Flatland. I'm not sure what will be but I am sure there is more depths to explore with the setting. Still, it's a pretty good try (and I am glad someone has made that try) and well worth the read. It would be fun to play.