The Great War (alternate Half-Life scenario)

by MrVibeIL

In this world, the Combine never subjugates the Vortigaunt race, instead getting stuck in a seemingly endless stalemate. When the Resonance Cascade occurred, the Vortigaunts sent an invasion force to Black Mesa, only to be thwarted by Black Mesa personnel and the U.S. military through the use of a nuclear weapon. When the Portal Storms begin, both sides use them to fight on Earth.

No one thought in the early 21st Century that Humanity would be so advanced in our technology, yet so primitive in our ignorance. Advanced AI, developing portal technology, and even limited inter-dimensional travel had been all but a pipe dream just a few decades before. But even with these revolutionary advances, we remained ignorant to the dangers these advancements posed to the Human race. To be fair, we had no idea of the enormous conflict taking place dimensions away, but even then, we should've known better than to try traveling between dimensions Humanity didn't belong in. In the end, this ignorance almost led to our complete and utter destruction.

For millions of years, two species had been at war with each other: the Vortigaunts and the Universal Union, or the Combine. Despite the Combine's technological advantage, the Vortigaunts were able to drive them into a brutal stalemate, utilizing their mysterious abilities to defend their home planet from the Combine onslaught. Countless years later, both sides had been waging a war of attrition, and no clear end was in sight. Right when this war began to cool down, and peace was considered, an event occurred that caught the attention of both sides. A Resonance Cascade had begun, opening large portals in the border world of Xen, one of the bloodiest battlegrounds between the Vortigaunts and the Combine due to the difficult terrain and hostile wildlife. The portals led to a new world, dominated by sentient bipedal creatures called Humans. Humans had been spotted exploring before, but both sides were too preoccupied with other matters to care about smaller, temporary portals that vanished within a few hours. Little did they know that this mysterious species would prove pivotal in the future war effort.

At the Black Mesa Research Facility in the New Mexico Desert, Doctor Wallace Breen was instructed by a mysterious businessman in a suit to use a specific sample in the next Anti Mass Spectrometer test. While the man claimed that this would bring great results for Humanity and possibly unknown allies, Breen was hesitant at first. However, he wanted to advance the project in order to maintain funding from the United States Government and the U.S. Military. So, he pushed the staff of Black Mesa to their limits, as well as the machines there. On May 16th, 2003, what was supposed to be a routine experiment on a new Xen sample went wrong in every possible way. The Black Mesa Incident had begun, and all hell broke loose. As security personnel were quickly overrun from the hostile aliens, they began to notice their cohesion and organization. They weren't simply running about causing chaos, they were organizing themselves and were advancing through the facility with strategy and planning.

Around a day into the incident, the Hazardous Environment Combat Unit (HECU) were deployed to assist Black Mesa Security Personnel in securing the area and pushing the hostile aliens back through the portals if possible. However, this force was quickly brought into combat with hostile Vortigaunts and Mantarays, alien airborne creatures that were able to destroy M1A1 Abrams tanks and V-22 Osprey VTOL aircraft with little to no effort outside of maneuvering over the target. The Vortigaunts were able to use their abilities to easily pierce armor worn by Infantry, and were extremely agile. The battle quickly turned into a rout as the HECU were forced to retreat, even with support from the Army and Air Force, as well as Black Ops agents sent in secret by the U.S. Government. Following a swift evacuation of essential personnel, Black Ops agents detonated a thermonuclear warhead, destroying the facility and ending the Vortigaunt invasion. Immediately after this, the United Nations and the North Atlantic Treaty Organization were both informed about the incident and the possibility of disastrous consequences for the rest of the planet. Soon, those words came true as portal storms began appearing all over Earth, dropping both Xen wildlife and an organized Vortigaunt invasion force tasked with securing Earth as a possible base of operations in the event they lose their homeworld to the Combine.

The Great War had begun.