Orcs attack your planet

Huge industrial world, it has large cities with robotized factories dedicated to producing ammunition. This is both a blessing and a curse. On the one hand you will not lack ammunition to fight the orcs. On the other hand everything is full of explosive things.

There are about 100,000 men, but they are armed only with lasguns and no heavy weapons of note. They are also not well trained or disciplined, but they fight to defend their home. An Imperial Guard regiment can arrive within a week.
The commander of the local garrison is Scaloni, a competent man who knows that his resources are limited. The governor of the planet is Menem, and he is extremely corrupt.

The Imperial Guard has a regiment nearby. They are smaller than the local garrison. But they are better equipped and trained, they have artillery, tanks and heavy weapons. They are commanded by Colonel Facundo, an ambitious man willing to prove himself. They are supervised by Commissioner Emiliano. This commissioner is different from many in the empire, he is wise and will order the evacuation of the planet if he feels that he cannot contain the orcs.

The orcs or greenskins arrive with a great army, some 90,000 waaaagh-ready boys, plus thousands of their gretchling servants. They are fiercely aggressive, loving hand-to-hand combat and exploding weapons. All they want is a good fight to honor their gods Gork and Mork.
The orcs have huge machines, but they look like they're made of scrap metal. They are led by their warchief, Mape elden gruk, a 6-meter tall and very aggressive orc warlord.