At least one to be used in the weapon, one as a backup for reloading, and another when you need to restock ammunition after a mission. You should keep the ammunition you find for each alien weapon initially.Later, when you start using alien weapons, keep as many as the squad needs of each weapon and sell the rest.Keep completely intact UFOs in your UFO yards, and sell the damaged ones that have been shot down.While you can sell alien weaponry and armour to make money, make sure to keep at least one of each type for research purposes.You can save on production and purchase costs by using the transfer feature, sending items from an oversupplied base to an under-supplied one.UFO terror sites and crashes even have a chance of disappearing if you take too long to respond. And the quicker you get somewhere the better, as the nations don’t like the aliens hanging around for too long. This will reduce response time when aliens land in an area. You should strive to have a base on every continent.All future rooms and features are dependent on these. A new base’s starting rooms should include a command centre and a power plant.You’ll need a workshop to carry this out. Always have enough labs, living quarters, and scientists to research alien technology, and then put the knowledge acquired to good use by producing new items and weapons for your base, aircraft, and soldiers.Make sure to research laser weapons which will give your troops a better chance against the aliens, and to better defend your base as well.If there are any areas that are not covered, you can build standalone radar installations. You should have bases’ radar signals overlapping so as not to allow UFOs to slip through any gaps. A base should be surrounded by at least two or three SAM sites, all with overlapping radii of fire.Yes, you don’t have to engage the aliens on board in combat, but you also don’t have a chance to capture aliens and their technology for research. Shooting UFOs down over the sea has pros and cons.Then when they get close you can either attack them or make your interceptors return to base and let your base defences take the UFOs down. You can launch interceptors or even dropships to lure fighter-class UFOs near your base and SAM site installations.The downside is they aren't as accurate and are weaker against enemy fire. Only use Saracens for long range combat, because they have more fuel and are faster. Preferably, you should launch Stiletto interceptor aircraft when UFOs are within the radius of your base’s SAM defences.Every base should have at least two heavily armed and armoured interceptors ready and primed to take on enemy UFOs.But you likely won’t have them sitting around if you’re smart anyway. In version 2.5 (unreleased at the time of writing) this is especially important seeing as higher ranked soldiers are paid more.This would be much easier if you could save soldier weapon and gear loadouts, but you can’t for now. You could even dismiss all workers, scientists, pilots and soldiers and just rehire them in the new month, if you’re feeling very scroogey. Otherwise their salaries cut in to your monthly upkeep and admin costs and that’s a waste. When it gets near the end of the month and you are due to receive funds from all the nations, make sure to dismiss scientists, pilots and workers who aren't working, and soldiers who aren’t… soldiering.

Ufo alien invasion game tech tree