Sibling rivalry is in the air as Bohemia Interactive's Arma 2 prepares for conflict with Codemasters' Operation Flashpoint series - both games stem from 2001 classic Operation Flashpoint, and both are targeting April opportunities to win further custom.

Having developed the original Operation Flashpoint, a tactical military shooter noted for its dedication to realism (post-traumatic stress notwithstanding), Bohemia Interactive opted to part company with its publisher Codemasters.

With that in mind, Bohemia Interactive's 2007 PC game ArmA: Armed Assault can be considered a direct sequel to OFP, upgrading the original's game engine and building on the original's online and offline features.

Codemasters' response came with Operation Flashpoint: Dragon Rising in 2009. They kept the name, leveraging OFP's reputation for realism, but used their own in-house engine and produced a game for Xbox 360 and PlayStation 3 as well as PC.

Its own successor, Operation Flashpoint: Red River, is due for release during the week of April 21. Arma 2 has been applying the spit and polish with a March 23 game update and Reinforcements, an April 1 disc compiling two recent expansions.

Codemasters is one of many publishers looking to establish a money-spinning military shooter franchise, just as Activision has done with the lucrative Call of Duty.

THQ rolled out Homefront earlier in March, and Sony attempted to widen the appeal of the Killzone series with February's Killzone 3.

Electronic Arts, though, seems to have the best chance of diverting attention from Call of Duty: Modern Warfare 3, having started its big money Battlefield 3 hype machine in earnest ahead of a fall 2011 clash.

The website for Operation Flashpoint: Red River is, while Arma 2 can be found at