Xenonauts is a PC strategy game due for release in 2013. It is a spiritual successor to the classic X-Com strategy games, putting the player in control of an organisation defending the world from an alien invasion.
It is a grand strategy game that involves building and managing bases across the entire planet, controlling jet fighters and ground troops in battle against the alien forces, then researching captured extraterrestrial technology to unlock their secrets!
Linux version uses WINE.
This is an example of how the Light Scout UFO type appears if attacked on the ground while landed (undamaged).