Killzone (PS2)

Years ago, the success of planetary colonization resulted in the human settlement of several planets. The majority of these colonies have aligned to form the ISA. However, a ruthless, militaristic separatist faction known as the Helghast has distanced itself while secretly planning to scale an all-out war. Killzone takes place during the initial Helghast blitzkrieg of the nearby colony of Vekta. When Vekta City's orbital defenses mysteriously fail, the Helghast land and deploy their troops rapidly and with ease. As the planetary defense forces are overrun and scattered into the city, your first objective as an ISA member is to escort a high-ranking official to an evacuation point. Drawing inspiration from classical military conflicts of the 20th century, Killzone captures the intense reality of warfare between the ISA and the Helghast. [Sony]

https://www.metacritic.com/game/playstation-2/killzone