The Eternaut

RPG based on the book El Eternauta (classic Argentine comic). An alien invasion has begun, and it begins with a strange, very shiny snow that kills everything it touches. Exposure to snow is lethal, and some people will improvise isolation suits to escape as soon as they discover this fact.

The master aliens "They" direct their subordinates, the commanders (humanoids with many hands) from an unknown base, and these in turn command all kinds of creatures that do the dirty work.

The aliens have a device on their necks that equates fear with tradition and kills them instantly if they feel fear.

Survivors will organize militias to defend themselves; survivors will build makeshift astronaut-like suits. Survivors will use firearms.

The streets are empty and deserted, desolate with snow-deprived death. The government as such has collapsed or is close to doing so.

Aliens are tremendously intelligent
The aliens set up traps, ambushes, false radio messages, and pretend to be rescuers.
The aliens want to empty the planet to control the biological mass.
The aliens have devices that detect the intentions of those who approach. They don't pass through walls.