Progress until near the end of the game under the Classic difficulty setting. Note: You will need to save and reload the game frequently. Use a sniper in a flying suit, preferably with Psionic abilities and the Double Tap ability. Equip him with a plasma rifle and wait for the small alien craft to appear. Shoot it down so some aliens will die and save some time. At the start of the mission, fly up with the jetpack and move towards the alien craft. The Double Tap ability will help you to kill two enemies in one turn, and the flying suit will help kill them from a distance. However an Etherals can mind control you. Frequently saving and reloading will solve this issue. Select the Classic difficulty setting. If available, use the "Second Wave" option "Save Scum" to allow new seeds if you get a bad outcome. Develop and build the Hyper Wave Relay and have Colonels. The Hyper Wave Relay lets you know exactly what will be encountered at a crash site, and thus avoiding getting surprised by Etherals. Do this against a Small Scout, which typically has between five to twelve aliens on board. Foundry should also have been built. Play as a Heavy with Ammo Conservation to minimize reloads and Deep Pockets to carry extra grenades. Also set up with Bullet Swarm (shoot twice), Shredder Rocket (extra rocket), Rapid Reaction (second shot on Overwatch after a hit), Grenadier (with Alien Grenades), Rocketeer (additional normal rocket). Equipment should include Heavy Plasma, Blaster Launcher, and Titan Armor. If playing with Enemy Within, also consider Neural Dampening, Hyper Reactive Pupils, and Forget the Meld.