XCOM: Enemy Unknown

Also see the page for XCOM: Enemy Within.

• The most important upgrades from the Officer Training School are the ones that increase party size. Get them ASAP.

• No one is invincible, but Rookies are cheap.

• SHIVs take a lot to build. By the time you've gotten them formidable, they're probably outclassed by just about everything, so either be ready to throw yourself into SHIV research, or don't feel bad about passing them up.

• Interrogations usually make research in some other area go quicker, so do those first when you can.

• Assaults can equip rifles in place of their default shotgun. A shotgun Assault plays completely differently from a Rifle one, and using one like the other will quickly get them killed.

• There's an Assault skill that makes the first Reaction Shot against that character each round miss. Get it, it increases their survivability by leaps and bounds, and the other skill is only good with a very specific, specialized build.

• A powerful psychic is extremely good and it can be worth training one up before the story requires you to.

• If you want to break the game in half: Get a Sniper with Squadsight, Damn Good Ground, Double Tap, put them somewhere high up, and rejoice in your angel of death..

• Always, always be ready to fire 2-3 satellites into orbit at the drop of a hat. Get your engineers going early (and make sure you have a lot of them!) and make uplink construction a priority.

• Countries with 5 panic dots will leave XCOM at the end of the month. Satellites placed in a country reduce panic a little immediately. You don't get any income from them until the monthly report. Therefore, a good idea is to hold onto your satellites until the day before the report, and launch them into any countries with full panic.

• If you haven't spotted aliens yet, best thing to do is take your move action and Overwatch with everyone. Don't dash into unknown territory.

• Flank, flank, flank. If you sit around taking potshots from cover for ages you'll get nowhere.

• Beelining for lasers is a good strategy, the increase in killing power is extremely noticeable and being able to reliably kill Thin Men in a single shot is a massive boon.