"... defined as either entertainment featuring and celebrating the military, or controlled by the military." --Wikipedia
Alternate name: Military entertainment
The first video game about Militainment was released on November 1998.
These depict modern and possibly past military operations in as realistic manner as you can with video games, many falling in the genre of serious games and some used by military for training their marines, and/or selling off the "glory" of being in the military.