Overwatch: Tips on Playing as Mercy

I have played as Mercy a lot in Overwatch. One reason is because random teammates often avoid choosing Support characters and thus I would have to cover the need. The other reason is because I like Mercy's weapon.

Mercy is Dr Angela Ziegler, the German-speaking Swiss. As a medic and scientist, she has done research in nanobiology for the treatment of illnesses and injuries. She is equipped with the Valkyrie swift-response suit for treating battlefield injuries.

Mercy's primary role is as a healer. As a Support character, Mercy's main drawback is that she can only attend to one patient at a time (disregarding her Ultimate Ability). Despite her role, Mercy is equipped with a reliable weapon that is potentially dangerous when wielded correctly.

Below are tips on playing as Mercy. I have also added a few tips on working with Mercy in the team at the end of the article. More will be added to this article as I learn more.
(Last update: 6 July 2016)

Preparation

Before playing a game, put in some practice. A 10-minute session in training (the time of one match) on the Practice Range will allow you time to develop and practice tactics in a stress-free environment. Count the number of shots it takes to defeat a training bot (it has 200 HP). Count the time taken to defeat a training bot. Try headshots, rear shots, body shots, long range shots. Try shooting lateral-moving targets at different distances. Mercy's Caduceus Blaster is powerful but one glaring feature is its medium shot-speed, which is both an advantage and a disadvantage. A lot of practice is necessary to compensate for the disadvantage.

Play around with damage amplification with the Caduceus Staff. Note the distance for it to be active. Try looking elsewhere while the Staff is in use.

The main requirement to use Mercy is battlefield awareness. The player must know the state of the other players. To practice that at the Practice Range, try defeating the four wandering Training Bots while simultaneously keeping the two Friendly Bots under fire alive.

Try out different characters to have a rough idea of their abilities. At least note their HP and whether they have shield or armor.

There is not enough time to learn everything in a 10-minute session and it will be incredibly boring to delay real play until you are ready. Instead, practice a little everyday (or each time before you play Overwatch). Each session will allow you to prepare much to try out in the game after.

Learn how to perform triage in Overwatch. Because Mercy can only attend to one patient at a time (unless her Ultimate ability is used), she has to decide whom to attend to first. Learn to recognize which of your patients require urgent attention and which can be left for later. This is an easy enough skill to learn by observing the play of other players and seeing the effect of your actions. By playing lots of games with Mercy, you will get better at determining whom to focus your attention on.

Strategy

Playing as Mercy requires battlefield awareness. You need to know the state of other players at all times.

Beginners usually go with the support strategy where they hang back and actively support the team by taking care of 6 patients (herself included). The player needs to keep track of who is injured and in need of healing, and who is on the offense and can use a damage boost. While attending to one patient, keep an eye on the condition of other patients. Some judgement is required on which patient needs the most attention while keeping Mercy out of harm (she's no good if eliminated). It is also important to note the position of teammates so Mercy can use Guardian Angel to escape in their direction.

A better use of Mercy is a balance between supporting your team and going on the offense. This requires keeping track of 12 patients, with 6 of them requiring the use of a different tool. Mercy's Caduceus Blaster is powerful, reliable and, when used correctly at the right time, can prevent damage by pwning the opposition before they can do further harm to your team. Since the Caduceus Blaster reloads while the Caduceus Staff is active, Mercy can still contribute to the team while waiting for her Blaster to be ready. It requires great judgement to decide when to heal/support the team and when to actively protect your team. Split-second decisions require information, hence the requirement to be aware of the condition of the player's team and the opposition at all times.

In Escort games, Mercy can escort the Payload. She is smaller than a Tank so it is easier for her to hide behind the Payload. Also, she can heal herself. This along with healing from the Payload (only if Mercy is on the attacker's side) can keep her firmly stationed at the Payload. This allows the rest of the team to actively mop up any obstruction to the Payload's advance. Keep moving to avoid from being shot in the foot through the bottom of a Payload that has a high ground clearance.

The Payload can be a mobile base. Teammates who are out clearing the way can return to the Payload for healing (from Mercy and the Payload) before returning to combat. Watch for attacks from the rear.

Tactics

Mercy's Caduceus Staff is capable of healing or providing a damage boost of 30% (so says the wiki at the time of writing). It takes experience to quickly determine who to heal. Sometimes, it is better to heal a less wounded ally instead of a critical one who may die from the next sniper hit. Some characters can heal themselves so those who cannot should be assigned a higher priority. Sometimes, it is better not to fully heal a character so a critically wounded ally may be attended to. There are no fixed rules, just many considerations. Experience will help you to decide on what to do.

In general, damage boosting should be used on characters with high damage like a sniper or Bastion on Sentry Mode. It is also good on characters who are using their Ultimate Ability like Pharah. Another occasion to use damage boosting is if the battlefield is too dangerous for Mercy to enter. At that time, it may be better to hang back in safety and boost (rather than heal) an ally so they can finish their opponent before more damage is done. A good question to ask often is if it is more effective to boost an ally, or to pull out the Blaster and directly deal damage.

When Zarya uses her ultimate ability, Graviton Surge, it is a good time to boost the damage of someone with area effect damage, someone like Zarya. If Zarya's player is good, she will keep her Energy up before using Graviton Surge to catch multiple opponents. Damage boosting will allow her to deal even more damage with her area-effect alt-fire.

One form of life-preservation is damage prevention, by eliminating sources of damage. As such, sometimes it is better for Mercy to pull out her Blaster instead of trying to heal or give a damage boost.

Mercy's Caduceus Blaster does a good amount of damage, has a large clip and has no deviation in its aim. However, it only has medium bullet-speed, which is both an advantage and a disadvantage. The major disadvantage is that, after firing the Blaster, the target may not be there once the shot reaches. To compensate for this, practice is necessary, especially against laterally-moving targets at a distance. Aim for where the target is going to be, rather than where it is. It takes experience to guess what a target is going to do and practice to determine where to aim.

Note that the Blaster reloads while the Caduceus Staff is active. Mercy can switch to support while replenishing ammo before returning to active damage-dealing.

The features of Mercy's Blaster makes it good against most Tanks. The Blaster's high damage seriously weakens the Tank for teammates to finish off. In addition, the Tank's size makes it easier to hit at a distance. However, Mercy is not as effective against Zarya. Zarya is a smaller target and her Shield automatically recovers from damage. In addition, Zarya can protect herself with her Particle Barrier.

The advantage of the medium bullet-speed is that the Blaster is good for sniping at turrets. At extreme range, Torbjörn's turret only reacts when attacked. Because of the Blaster's medium bullet-speed, Mercy can put a few shots in the air before the turret notices it is under attack. Mercy can then duck back behind cover while her last shots are still in the air.

The Blaster's medium bullet-speed is also good to suppress snipers, especially Widowmaker. Mercy can put bullets in the air towards where a sniper will appear then slip back into cover before that sniper does show up. This allows Mercy to attack without putting herself in danger. Even if Mercy does not eliminate the sniper, having bullets flying around and doing damage is very distracting to all but the calmest of snipers.

If no one needs healing, and there are only targets in the distance, Mercy can draw her Blaster and chip away at the targets' HP to make it easier for allies to defeat them. Another good time to have the Blaster out is to defend yourself from Tracer, especially when there are no (reliable) teammates to help.

An obvious time to use the Blaster is when a teammate is incapacitating a target. While Roadhog is pulling in his target, he cannot attack. While the target is in a predictable position, Mercy can fill the target with bullets. It is similar when Mei is freezing a target. It is also applicable when Reinhardt is charging, though you need to be quick in determining where he will stop. Mercy can also attack the opposing Roadhog or Reinhardt when either is using certain abilities and is predictable.

Also pull your Blaster out when your team's Reinhardt has his Barrier up and is not making any move to get closer to the target. That is, unless someone is in need of medical attention.

Engage Bastion in Sentry Mode from long range and from cover. If you peek out from cover (say, from behind a wall) such that you can only see a tiny part of Bastion, the chances are Bastion can only see a small part of you. At long range, Mercy's Blaster is far more accurate than Bastion's weapon. As such, all of Mercy's shots will hit while some of Bastion's return fire will hit the cover. This situation allows you to do your full damage to Bastion while taking only reduced damage in return. Keep an eye on your health in case Bastion increases its accuracy by firing in intervals or is somehow dealing more damage than expected.

Mercy's Guardian Angel ability can be used to move to different patients quickly. It can also be used to flee combat. One feature of this ability is that it can be cancelled early by pressing the button to activate the skill again. Do this to stop Mercy short of an ally in the line of fire.

Frequently, it is best to flee battle. Because of Mercy's usefulness in and out of combat, it is best that she remain alive and active at all times. Always look for escape routes in preparation for sudden attacks. Learn to watch (and listen) for sniper fire. Note the position of distant allies so you can use Guardian Angel to fly to them quickly.

Mercy's health regenerates on its own if she does not take damage for a while. As such, it is possible to take a few hits to protect an ally before ducking into cover to 'self-medicate'. Since Mercy does not have to do anything to heal herself other than avoiding damage, this is one situation where she can attend to two patients at once.

One situation where Mercy should take a hit is to save a frozen teammate from Mei. Usually, once Mei freezes an opponent, she would follow up with an icicle to her target's head. By using Guardian Angel, Mercy can fly to the ally as he/she is being frozen, then jump (to avoid getting hit in the head) in front to take the icicle. Keep firing at Mei to chase her off. It takes a bit of practice but it is possible to start shooting while Guardian Angel is moving you to your ally.

Do not try the above against Roadhog. A skilled player of Roadhog can eliminate Mercy quickly if she gets too close.

Mercy and Pharah can form an air force. When Pharah boosts into the air, Mercy can use Guardian Angel to follow and either provide fire support or attend to allies from the air. Being in the air allows Mercy to survey the situation better while avoiding attacks that are weak against flying targets. Using Angelic Descent allows her to maintain height advantage longer. Do watch for anti-aircraft capability on the opposing side before using this tactic and be ready to drop into cover if there is danger, especially if it looks like an opponent is taking careful aim.

Symmetra is very powerful in close-range skirmishes, if she stays alive. Mercy can keep Symmetra active longer or boost her already considerable damage.

Working with Mercy

Working with Mercy in the team requires a few considerations to get the best out of her. The first of which is not to be reckless just because Mercy is in the team. Mercy can only treat one patient at a time and so can easily be overwhelmed with work. When she is not treating an ally, she can deal heavy damage with her Blaster.

Do not rely totally on Mercy. She's good for fixing minor damage and preparing survivors for the next engagement. However, if you have taken major damage, it may be better to step back and look for Health Packs so Mercy can concentrate on allies that can contribute better, who would not die from the next hit. On the other hand, letting Mercy heal you charges her Ultimate Ability faster.

Do not overwhelm Mercy with requests for healing. Triage is an easy skill to learn (Disclaimer: triage in Overwatch, not in real life!) with experience so it is safe to assume most players of Mercy know which patient to prioritize. Trying to influence her decision with repeated requests may bring down the team by denying support to important players. If Mercy does not respond to your request for healing, she must be attending to someone with a greater need or even trying to save a teammate from an opponent. Or she may just be looking the wrong way.

If you are Pharah, check for anti-aircraft capability in the opposition. If it is safe, take to the skies often so Mercy can join and provide air support.

If you are a sniper or someone who hangs back, be somewhere visible to Mercy (if it is safe). That way, she can use Guardian Angel to flee to your position if she is in danger. In addition, she can come to your rescue or attend to your wounds. When on a high position, stand near the edge of the ledge because the ledge can block Mercy from using her Guardian Angel.

'Primum non nocere' is Latin, which means 'First, do no harm'. This is a weird phrase to put in Overwatch, on someone with a powerful weapon.