Twenty eight out of twenty nine achievements in GOME can be completed solo. It is only "No Head Left Uncracked - Damage every Guardian once in 5 vs 5 Matches" that requires an extra player to complete as there are certain characters that the computer never selects. Though finding a plus one either in the forums or comment section below should not prove to difficult. (NOTE: When going for the 5v5 achievements. It takes the computer 5 minutes to notice that no one is online & puts you in a match with all hard robots)

Honor in Death
Fall on the Battleground


Easiest achievement all you need to do is simply die.

Win Your Way
Win a Private Match


Simply make a custom game & win it.

Rule Them All
Win any 3-Lane 5 vs 5 or Co-Op vs Bots Match


Even though this achievement states that you need to win any 5v5 or coop vs bots match, this is false. This achievement can only be obtained by winning a coop vs bots match.

Foe's Bane
Achieve a Kill Streak of 3 in any 5 vs 5 Match


This can be obtained through natural game progression or while boosting "Renowned" (See below in Multiplayer Recommended Achievements)

(MVG) Most Valuable Guardian
Earn a combined Guardian Kill/Assist Streak of 8 in any 5 vs 5 Match


This can be obtained through natural game progression or while boosting "Renowned" (See below in Multiplayer Recommended Achievements)

Rise to the Top
Reach Level 14 in any 5 vs 5 Match


You will more than likely be level fourteen by the end of most matches so I would not worry about this one.

Capture the Power
Capture 15 Shrines total in any 5 vs 5 Matches


(Cumulative) Just keep capturing shrines in each match and you'll soon unlock this one.

Draught of Courage
Use 4 Potions in any 5 vs 5 Match


Start a match. Not equipping any items to your belt & potions bar the game will ask you if you want to use that guardians default belt, potions, & commands. Hit yes. Once in game simply use all four of your potions & the achievement will unlock.

Master Mason
Upgrade 3 Towers in any 5 vs 5 Match


Once you reach level six walk up to a tower & press "U" select the "Quickfire Tower" This is the only option you can select at this level which is located on the left. Repeat two more times & this achievement will be yours.

Rally the Troops
Build 6 Soldier Upgrades total in 5 vs 5 Matches


(Cumulative) Once you reach level six walk up to a soldier deployment station & press "U" select the "Barracks" This is the only option you can select at this level which is located on the left. Repeat five more times & this achievement will be yours.

All Falls Before You
Destroy 5 Soldier Upgrades total in 5 vs 5 Matches


(Cumulative) Whether you choose to get this in a one or three lane 5v5 match make sure that when your A.I allies go to destroy it that YOU get the last hit otherwise your destroys will not count.

Drive Them Back
Achieve a Multi-Kill of 2 in any 5 vs 5 Match


Most easily achieved in a one lane 5v5 match using Agandaur (Suggested Relics & Gems are listed below under in Enchanted Build)

Ultimate Vengeance
Use an Ultimate Ability to defeat an Enemy Guardian in any 5 vs 5 Match


Can be easily unlocked using the same method as listed above.

In Command
Use a Tier-4 Command in any 5 vs 5 Match


Even though this achievement states that you must use a tier 4 command in any 5v5 match, this is false. You will have to kill the opponent in a 5v5 match using a tier 4 command for this to unlock. First things first you're going to want to select "Summon Defence" which is located in the top right corner of your commands. This move summons either an Ent or Balrog which will lower their resistance by 30% as well as damage them for 6% of their max health for the next 7 seconds. It is best to get the enemy down to around 10-15% health before casting.

Collector
Kill or Assist a Guardian from each Class once in any 5 vs 5 Matches


(Cumulative) If you are sufficiently attacking/ defending you should get this through natural progression. If not simply hunt down & kill every member of the enemy team at least once. The enemy team always chooses one of each class & never two of the same character. This makes it easy for you to mark down who you have and haven't killed.

And My Axe
Achieve an Assist Streak of 5 in any 5 vs 5 Match


If you wish to get this achievement done quickly I suggest one lane 5v5 match. It is possible to get this in three lane but chances are that it would take much longer. Damage an enemy close to death & then let your comrade finish them off. Repeat four more times.

Seasoned
Earn 5 Accolades in any single 5 vs 5 Match


(Unlocked at end of the match) To obtain this achievement you must complete five accolades (in game tasks) in a single match. Aim for more that five to be safe. Here's a list of a few of them to get you started.

• First Shrine Captured
  
• Most Shrines Captured
  
• First Tower Upgraded
  
• Most Towers Upgraded
  
• First Soldier Den Upgraded
  
• Most Soldier Dens Upgraded
  
• First Tower Destroyed
  
• Most Towers Destroyed.
  
• Last Hit On The Final Tower
  
• First Kill
  
• Fewest Kills
  
• Zero Kills
  
• Longest Time Survived
  
• Fewest Deaths
  
• Longest Distance Travelled
  
• Least Amount of Healing Used
  
• Player Who Used Most Commands

Notches in the Axe
Earn 50 Accolades total in any 5 vs 5 Matches

Take note of some of the accolades I have listed under above. As long as you are unlocking one or two a match this should come through steady progression towards your 100 wins in 5v5 matches.

Warrior's Mettle
Win with a Warrior-Class Guardian in any 5 vs 5 Match


Win a 5v5 match with one of these selected heroes.

• Thrain - Free
  
• Ugluk - 5000 gold
  
• Mozgog - 5000 gold
  
• Sauron - 5000 gold
  
• Arathorn - 5000 gold
  
• Beregond - 5000 gold
  
• Glóin - 5000 gold
  
• Thorin - 5000 gold

Strike Hard, Strike Fast
Win with a Striker-Class Guardian in any 5 vs 5 Match


Win a 5v5 match with one of these selected heroes.

• Legolas - Free
  
• Gollum - Free
  
• Haldir - 5000 gold
  
• Unglob - 5000 gold
  
• Bilbo - 5000 gold
  
• Frodo - 5000 gold
  
• Snaga - 5000 gold
  
• Kili - 5000 gold

Defend to the End
Win with a Defender-Class Guardian in any 5 vs 5 Match


Win a 5v5 match with one of these selected heroes.

• Galadriel - Free
  
• Witch-King - 5000 gold
  
• Wulfrun - 5000 gold
  
• Éowyn - 5000 gold
  
• Mouth of Sauron - 5000 gold
  
• Great Goblin - 5000 gold

Enchanted
Win with a Enchanter-Class Guardian in any 5 vs 5 Match


Win a 5v5 match with one of these selected heroes.

• Gandalf - Complete Tutorial
  
• Agandaur - 5000 gold
  
• Sauron - 5000 gold
  
• Radagast - 5000 gold
  
• Lugbol - 5000 gold
  
• Ori - 5000 gold
  
• Barrow-Wight Lord - 5000 gold

Fortified
Win with a Tactician-Class Guardian in any 5 vs 5 Match


Win a 5v5 match with one of these selected heroes.

• Hildifons - Free
  
• Elrond - 5000 gold
  
• Runsig - 5000 gold
  
• Gothmog - 5000 gold
  
• Felgrom - 5000 gold
  
• Bert - 5000 gold
  
• Nori - 5000 gold

There And Back Again
Win 25 total 5 vs 5 Matches


Both three & one lane count towards this achievement. But one lane is suggested as it's quicker.

An Unexpected Journey
Complete 100 5 vs 5 or Co-Op vs Bots Matches


Even though it clearly states that you should either complete one hundred 5v5 or coop vs bots matches, this is false. If you want to attain this achievement you will need to WIN one hundred 5v5 or coop vs bots matches (Personally I used Agandaur in 5v5 one lane in 98/100 of my wins)

In the Light
Play as every Good Guardian once in 5 vs 5 Matches


As you progress towards your 100 wins you should acquire enough money to purchase all heroes. Simply complete one 5v5 game with each.

Guardians that count towards this achievement:

• Nori - 5000 gold
  
• Hildifons - Free
  
• Elrond - 5000 gold
  
• Ori - 5000 gold
  
• Gandalf - Complete Tutorial
  
• Radagast - 5000 gold
  
• Galadriel - 5000 gold
  
• Eowyn - 5000 gold
  
• Legolas - Free
  
• Haldir - 5000 gold
  
• Bilbo Baggins - 5000 gold
  
• Frodo - 5000 gold
  
• Killi - 5000 gold
  
• Thrain - 5000 gold
  
• Beregond - 5000 gold
  
• Arathorn - 5000 gold
  
• Thorin - 5000 gold
  
• Gloin - 5000 gold

Servant of the Shadows
Play as every Evil Guardian once in 5 vs 5 Matches


As you progress towards your 100 wins you should acquire enough money to purchase all villains. Simply complete one 5v5 game with each.

Guardians that count towards this achievement:

• Gothmog - 5000 gold
  
• Runsig - 5000 gold
  
• Bert - 5000 gold
  
• Felgrom - 5000 gold
  
• Lugbol - 5000 gold
  
• Agandaur - 5000 gold
  
• Barrow-wight Lord - 5000 gold
  
• Saruman - 5000 gold
  
• Wulfrun - 5000 gold
  
• Witch-King - Free
  
• Gollum - 5000 gold
  
• Unglob - 5000 gold
  
• Snaga - 5000 gold
  
• Sauron - 5000 gold
  
• Ugluk - Free
  
• Mozgog - Free

Renowned
Earn 20 Guardian Kills in any 5 vs 5 Match


You are welcome to try this one on your own though I would highly recommend boosting this with a friend in a three lane 5v5 match.

No Head Left Uncracked
Damage every Guardian once in 5 vs 5 Matches


Personally I have only ever seen the computer select Hildifons, Gandalf, Wulfrun, Gollum, Ugluk, Gothmog, Eowyn, Beregond, Thrain, & Lugbol. That means that the remainder of the characters must be selected by another player in a 5v5 match for you to damage. Games will need to be completed for them to register & there is no in game counter for this achievement so it is best for you to keep track of who you have & have not damaged. ( I suggest working on "In The Light - Play as every Good Guardian once in 5 vs 5 Matches" & "Servant of the Shadows - Play as every Evil Guardian once in 5 vs 5 Matches" alongside this achievement as it will save you some time.)

Thorin

Red Book Relic
• 5% Life Steal
  
• 5% Life Steal

Goblin-Gate Relic
• 4% Basic Attack Damage
  
• 10% Critical Damage
  
• 6+ Basic Attack Penetration
  
• 10% Critical Damage

Empty Gem Slot
• 10% Critical Damage

Legolas

Swift Blade Relic
• 5% Attack Speed
  
• 5% Attack Speed
  
• 4% Movement Speed

River Barrels Relic
• 6% Basic Attack Resistance
  
• 5% Attack Speed

Durin's Day Relic
• 5% Attack Speed
  
• 5% Attack Speed

Hildifons

Blue Mountain Relic
• 24+ Ability Power
  
• 24+ Ability Power
  
• 5% Ability Cool Down

Westernness Relic
• 5% Match Experience Gained
  
• 24+ Ability Power
  
• 6% Ability Lifesteal
  
• 6+ Ability Penetration

Agandaur

Tendric Relic
• 24+ Ability Power
  
• 24+ Ability Power
  
• 24+ Ability Power
  
• 5% Ability Cooldown

Black Gate Relic
• 6+ Ability Penetration
  
• 6+ Ability Penetration
  
• 1.6 Health Regeneration Per Second

Galadriel / Eowyn

Iron Hills Relic
• 6% Basic Attack Resistance
  
• 5% Ability Resistance

Miruvor Relic
• 1.6+ Health Regeneration per second
  
• 45+ Max Health

Bastion of the West Relic
• 6+ Basic Attack Damage
  
• 5% Ability Resistance
  
• 6% Basic Attack Resistance