What's the quickest way to get all of the achievements in StarCraft 2?

Preface

StarCraft 2 has a lot of achievements. There are almost a thousand different achievements available as of 2016. When you say "get all achievements", this is a really big task. If you are an achievement completionist, you probably want to define some more realistic goals with respect to StarCraft 2, such as just completing the campaign achievements, because to actually get them all will take a very long time. The reason for this is the Multiplayer category. All of the other achievement categories combined (all three Campaigns, Mission Packs, Custom Games, Exploration, Arcade, and Co-op) will take you less time to complete than the Multiplayer achievements. The following analysis will show why, and just what kind of time scales we are looking at.

Multiplayer Achievements (Skyrim X10)

In this category, there are two achievements in particular that are the big nasties: "Solo Zen Master" and "Team Zen Master". Each of these require you to win 1000 games with each of the four race options: Terran, Zerg, Protoss, and Random. "Multiplayer Zen Master" use to be a third demon on the list, but since they removed Free For All from multiplayer matchmaking, they also removed the free for all achievements, making "Multiplayer Zen Master" basically meaningless now that it does not contain the "Win 800 Free For All games" achievement. Now, winning 1000 games as each race option in both solo and team is really hard for several reasons.

1. You can't make progress in any of the race achievements simultaneously except by playing Random. Playing as Random does give you progress in both Random and the race you ended up playing as, but this only reduces the needed number of needed solo and team wins from 4,000 to 3,000.
2. Solo and team are totally separate progress categories. Winning a 1x1 game only gives you progress in the solo achievement series and winning a 2x2 game only gives you progress in the team achievement series. There is no way to progress in both series a the same time. Thus, you need 6,000 wins total to get these achievements.
3. You need to win 6,000 times, not just play 6,000 games. StarCraft 2 has a pretty good online matchmaking system, meaning that for the sake of approximation (unless you are the best or worst player in the world), you will win 50% of the time. As a result, this will take approximately 12,000 games of StarCraft 2 to get this pair of achievements.

How long does this take? Let's make some assumptions. Let's say you have a fairly aggressive play style, preferring to attack early off of one or two bases rather than go for map control. This means you could have an average game length of about 20 minutes, so you can play 3 games an hour. Now let's say you have a full time job, but are dedicating the bulk of your free time to playing StarCraft. You can get in 4 hours every weekday and 10 hours on the weekend (leaving you a few hours to go out for beers and talk about StarCraft). This adds up to 40 hours a week of StarCraft. This means that it will take you 100 weeks to play the needed 12,000 games to get this pair of achievements.

To close out the Multiplayer category in its entirety, you also need to play another 750 games to get all the Versus AI achievements, but that only adds another 6 weeks on top of this. The rest of the achievements (Economy, Unranked/Ranked, and Melee Combat) can reasonably be expected to all happen in the course of your 12,000 games (worst case is if you have already lost a game, you ask your opponent to let you get one of these achievements before beating you).

Thus, devoting a full-time job's worth of attention (40 hours a week) to StarCraft 2, it will take you just over 2 years to get all of the Multiplayer achievements. That's enough time to play all of Skyrim about 10 times over.

The Campaigns: The "Achievable" Achievements

The Campaign achievements are far more reasonable as a completionist goal. Legacy of the Void is supposed to be the last big campaign for StarCraft 2, so let's ignore the Mission Packs (since we don't know how many of those there will be) and just deal with the three big campaigns: Wings of Liberty, Heart of the Swarm, and Legacy of the Void. To get all of the achievements in these is best done by playing through each campaign three times: once on normal, once on hard, and then once on brutal. This is not going to be the theoretical fastest way to get all the achievements, but going for all the achievements on a single brutal playthrough may prove difficult or in some cases impossible (for example, the Legacy of the Void mission "Into the Void" requires two playthroughs to get all of its achievements).

The theory of this system is on the normal playthrough, you get the bulk of the achievements, including all of the bonus objectives and achivments that require you to play on normal or harder. Then, on the hard playthrough, you get all the achievements that require you to play on hard or harder (these are the "Mastery" achievements in the Swarm and Void campaigns). Finally, on the brutal playthrough, you are just trying to finish. There are a couple advantages to the triple-playthrough style. First, you are only doing achievements on the minimum difficulty needed, meaning when you play on brutal, you don't need to also be hitting bonus objectives or doing other difficult things. Second, you get to play through the missions on an easier difficulty to understand them, allowing you to better plan for the harder playthroughs. Finally, you can replay individual missions on higher difficulty using the mission archives feature, meaning you can play missions on hard or brutal while still using all of the campaign advantages you accumulated on normal.

There are 29 missions in the Liberty campaign, 20 missions in the Swarm campaign, and 22 missions in the Void campaign (counting the epilogue). This is 71 missions total, each of which need to be played 3 times. Given that campaign missions are a little more involved than a multiplayer rush, let's assume 30 minutes per campaign mission. This means about 107 hours of campaign time to complete all three playthrouhgs of all three campaigns. Add in some time for the "Lost Viking" and "Hurry Up, It's Raid Night" achievements in the Liberty campaign (the few achievements that you don't get in the triple playthrough) and you're up to 120 hours. This is assuming you don't fail any missions and skip all of the cut scenes and dialogue. I would say 160 hours is a far more reasonable estimate.

Even so, this is still only 3 - 4 weeks of dedicated play to get all of the campaign achievements, which is so much less than the 2 years needed for the Multiplayer category. Also, these will give you far more achievement points than multiplayer. The campaigns are worth a total of 4900 points (1590 + 1520 + 1790), where multiplayer currently only has 2180 points of achievements. If you care about achievement points, the campaigns are the easiest place to get them.

Other Categories

Exploration, Mission Packs, and Arcade are campaign style achievement categories where it is just about doing potentially difficult things and don't have grind. These are pretty quick (the only exception being the "Play 50 ladder games" that got added to Exploration, but this happens in the process of doing any multiplayer achievements).

Custom Games and Co-op are the other two grind categories, but are much smaller in grind than multiplayer. In Custom Games, you only need 300 wins (100 with each race, at least 100 of which have been against the Insane AI) to close out the category. Similarly, Co-op requires a little over 500 games to get the "500 Brutal Missions" achievement, in the process of whcih you can get the "150 Brutal Mutations" and "100 Mutation Bounties" (and all the others), but this is also nowhere close to the 12,000 of Multiplayer. Note that winning on a higher difficulty gives you credit for all of the lower difficulties, so playing on the hardest level possible is the method to finish these as quickly as possible.

Assuming 20 minutes for a co-op mission and 10 minutes for a custom game (you can pick what strategy the AI uses, you you can get a huge advantage on this front), that's 50 hours to do the Custom Game achievements and 100 - 200 hours for the Co-op Achievements. Mission Packs, Exploration, and Arcade could probably all be done in around 50 hours (until they add more mission packs). So this is another 200 - 300 hours for the rest of the categories.

Bonus Round: Feats of Strength

There is the special achievement category "Feats of Strength" for achievements that don't give points but simply are there to commemorate awesome things you have done, such as your highest rank league finish or purchasing the collector's edition of the various games. Having all of these is really difficult. For example, if you missed the "Play a game during StarCraft 2's 5 birthday achievement", there is no way to get that now. You're hosed. Don't even try for having all of these. There are a couple that are pretty easy to get, like "The Scenic Route", "You're So Crazy", and "Monster Mash" that are hidden achievements for the Wings of Liberty campaign. Also, you'll probably get some pretty high league finishes if you actually play 12,000 games of StarCraft (likely Master League, if not Grandmaster League) just from sheer force of practice.

The quickest way to complete all the achievements (assuming you have sufficient skill level) would be to do it like this:

• Complete the campaign on Brutal, this will give you all the mission achievements below that require you to do it on hard difficulty as well (though in all honesty I had to do it twice, once on hard (also my first play through) to get through everything and then again on Brutal just to get it done). Also I did one on normal and only did the required missions to get through the game for the "Hurry up it's Raid Night" Achievement.
• To get all the Armory related achievements, on your normal/rush play through, save up all your money, buy all of one tier up upgrades (which will then give you the achievement) then reload your game and buy another tier. Make sure you don't save as it will give you all your money back at the reload point.
• With the ladder achievements, play random. When you get a win with random, it will also count as the race you randomed as. So random race as Protoss when you start the game you will get credit for one win as random and one win as Protoss. This goes the same with the Co-op games vs. AI.
• All the other random ones like, "Kill a full medivac", "Regen 500 HP on a roach", get "50 kills with one unit" (I BC rushed for this one and sent SCVs to repair), will all come in time as you get each race.
• Same rules apply with the co-op ones because most of them are race related (beat it on Random, gives you credit for random and the race you played as). Also for the difficulty related ones, do them on insane and they will give you credit for all the lower difficulties. Beat it on Insane and get credit for Very Hard, Hard, and Medium.