Xenonauts

In 1958, Earth made first contact. A UFO was spotted heading for the US. Ruled out as a nuclear strike due to its suddenly changing course for Iceland, it proved deadly to conventional aircraft and was grounded but not destroyed with the Nuclear Option. A joint NATO and Soviet force moved on the crash site, but took bitter losses and failed to recover anything of worth. In the wake of the Iceland Incident, the Xenonauts were clandestinely formed through West-Soviet collaboration. As time passed and further alien contact failed to materialise, however, funding and manpower was cut, stripping the organisation to the bone.

1979. An alien fleet arrives in Earth orbit, refusing communication and resisting almost all attempts to repel them. The sole success: A mysterious interceptor taking down a scout craft.

The world's governments receive calls from the Xenonauts, asking for funding and permission to operate in their territories against extraterrestrial forces...

Xenonauts is a Turn Based Tactics game where you command the eponymous organisation, sending interceptors and strike teams out to fight the alien menace. It is a Fan Remake of X-COM by indie developer Goldhawk Interactive. Its homepage can be found here and it is in preorder alpha status; preorderers will get to test the game as it undergoes development. Currently undergoing a Kickstarter campaign to raise money to add new features.

Tropes:

 * AKA 47: Aircraft include the "F-17", "MiG-32" and "CH-48".
 * Armor Is Useless: Averted. Even the basic armour allows your troops to survive what would be fatal to an unarmoured soldier, albeit badly hurt.
 * Chainmail Bikini: Averted. Female troopers' armour is sensible.
 * Dueling Games: With the new official installment Enemy Unknown, though Chris England is cordial about the competition.
 * Enemy Mine: The Xenonauts were formed through NATO-Soviet collaboration.
 * The Grey: Caesans.
 * With This Herring: Averted in the sense that you get lousy newbies only if you manage to get the reasonably-experienced starter squad killed.