Factions

Overview
As of update 0.8.1, released on February 12th, 2015, there are four factions with at least one robot and one faction that does not.

On the Facebook page of Walking War Robots, this picture was released, showing each robot currently available in game. There are a total of five factions:
 * TMC (Transatlantic Military Corporation): This group consists of one light robot, one medium robot, and two heavy robots.
 * RUS (Russian Empire): This faction is made up of a light robot, two medium robots, and one heavy robot.
 * GER (Neue Ordnung): The Neue Ordnung is made up of two light robots, one medium robot, and one heavy robot.
 * FFA (Freedom Fighter's Alliance): Currently, this group features a medium robot only.
 * PRC (People's Republic of China): This group features no robots so far.

TMC
The Transatlantic Military Corporation is most likely centered around North America and Western Europe. Based on the names of the robots (e.g. Gl. Patton), it is safe to conclude that they are probably centered around English-speaking nations. It is probable that these nations banded together into a capitalistic business that makes money by developing, manufacturing, and selling arms, as well as keeping a self-defense force of Walking War Robots.

Based on the types of robots maintained by the TMC's military, it seems that they focus on heavy assault; the general repetition of hardpoint types seems to be aimed at mass-mounting each robot with the same weapon to focus specifically on one type of combat. In addition, TMC robots seem to rely more on armor than on speed; they generally have slower speeds when compared to other robots of their class, but with a higher number of hitpoints.

RUS
The Russian Empire is most likely centered around Russia, Eastern Europe. Based on the names of the robots (e.g. Vityaz, from Latvian), the nations of the Russian Empire are probably closely-associated with Russia in terms of economics and physical distances.

Based on the types of robots operated by the Russian Empire, they seemingly emphasize versatility; the variety of hardpoints offered means that robots armed with long-range artillery can also be equipped with short-range weapons to defend against any situations that require closing with the enemy. Additionally, two of the four types of robots have the ability to jump, which further supports the idea of tactical adversity. The armor and speed of these robots seem to be quite balanced as well compared to the weight of their armaments; the Vityaz and Rogatka are excellent examples of this.

GER
The Neue Ordnung (New Order) probably contains Germany and Southern Europe. It probably shares its western border with the TMC and its eastern border with the Russian Empire.

From the types of robots utilized by the Neue Ordnung, it seems that they focus on using medium-speed robots in combination with faster robots that are armed with a combination of close-range and long-range weapons. The ability of most German robots with heavy hardpoints to also mount multiple lighter armaments stresses that these robots can be used either for a certain type of environment or for a variety of situations. German robots seem to have very high-speeds for their number of hitpoints, sharing the title for fastest robot (Gepard) with the Russian Cossack (when upgraded). However, the Gepard has more armor and firepower than the Cossack though without the ability to jump.

FFA
As of the most recent update (0.8.1), there is only one robot currently available: the Golem, a medium robot. Because of its name's root in Jewish folklore, the FFA may be centered around Israel. However, due to the game only having one of four robots available for the FFA, it is unknown whether other countries belong to the FFA.

Based on the only robot currently available, FFA robots seem to sacrifice armor for large amounts of firepower and a decent speed; the Golem shares a similar weapons loadout with the German Leo but with a little over half the hitpoints but a considerably better speed.

PRC
The People's Republic of China currently has no robots in game. However, based on the name, it can be safely assumed that it is centered around East Asia, specifically China.