Fortunately, for you, we have this comprehensive guide detailing the strategies you should adopt when facing these enemies.
Let us not waste any more time and start with our first enemy:
These are the first enemies you will encounter in the game. These guys are not armored, and they only use light plasma weapons. However, they can be a real handful as they have a nasty habit of flanking you.
Note that they have special racial ability that allows them to heal and buff each by creating a link between them. When you see this taking place just shoot the Sectoid that created the link, and both will die.
Do not let the name fool you, these scum bags are very hard to put down. These enemies are like the Sectoids but they are much faster and athletic. They also have an AoE attack so be sure not to bunch your troops up at one place.
Whenever you kill them, they explode into clouds of poison gas thus be sure to be far off from them when you are about to hit them with a final strike.
Floaters are flying robots so the terrain of the ground does not really matter much to them. They like to fly directly up and land behind your men so look out for that as well.
Always have a man on over watch to deal with this. They constantly travel in a group of three or two.
Outsiders can often be found on small flying saucers, and they have a tendency to appear out of the blue. They have more hit points than your usual enemies and can do some major damage with their plasma rifles.
Do not take them on when you are already engaged in a fire fight, wait until you have dealt with everybody else and only then fight them.
Do not fear old vets, these guys aren’t that terrifying as before. However, they are still pretty hard to beat. They have every attack in the book. They are speedy, poisonous and powerful.
They also have the ability turn their victims into zombies. Whatever you do not let these nasties get close to you. If they do, forget all about defense and try to destroy them as soon as possible before they do the same to you.
Fortunately, in XCOM Enemy Unknonn, their health is in the middle weight zone but that too is just a small comfort.
These guys are a ranged attack unit. They are more long-lasting than Sectoids or Thin Men, and they hit harder too. They tend to utilize grenades to draw XCom units out of cover.
No special way to defeat them other than just fire them all dead. Later in the game they come with upgraded armor and weapons.
They have more health and damage at their disposal than your average Sectoid. What sets them apart is that they can also use mind control on your men!
The best way to deal with these enemies is to use SHIV units against them, which can’t be controlled. Furthermore, strengthen your units’ will by Combat drugs and Psychic Inspiration.
These are flying robot med-kits of enemy units. The simplest way to deal with them is to chuck a grenade at them when they are busy healing an enemy unit.
They will be taken out in the blast as they have low h.p, and also you will deal damage to the other unit as well. Be warned sometimes they will be used as a distraction by the A.I so it can forward its other units from cover positions.
These UFOs cannot take cover so they are easy to hit. All is not that comfortable though as they have tremendous armor and deal heavy damage by throwing grenades at a long range if they have to. However, they are rather susceptible to HEAT rockets.
These guys carry no weapons they are just too hardcore for that shit. They have a fearsome melee attack that deals immense damage.
Note that every time they are attacked, and they survive they get an extra turn. Thus focus all your man power at them whenever they become visible before they come too close to your troops and utterly vanquish them.
Sectopods are strong like seriously tough. They have a lot of health and deal a lot of damage. Best way to engage them is to use shredder rockets and HEAT rounds against them. Note that you should only engage them head on if you have a full cover.
These aliens are the who’s who of the alien races. They are the most lethal and fearsome creatures you will come against in the game. They can control minds, deal psychic damage and do various other things. Ethereal are usually guarded by Muton Elite squads.
Avoid fighting against them in close quarters at all cost. Best way to take them out is to spam them with missiles as they cannot deflect AoE attacks like everything else they normally deflect when you fail to hit them.