Completing Achievements gives you rewards in the form of Experience and Gems. Your Achievements will also appear in the Game Center and on your Profile; each Achievement gives you a set amount of Game Center points.
Since the "Player Profile" update, player's achievements/status (including overachievements) are made public. The 19/12/16 update replaced the Achievements button with the Events button, making Achievements only visible through Player Profile. However, some events function like mini-achievements with limited time period.
There are 36 Achievements currently available. The "Keep Your Village Safe" and "Dragon Slayer" achievements have only one level each with gives all three stars; the others each have three levels, for a total of 104 levels:
|Home Village Achievements|
|Achievement||Data involved||Requirements||Experience Rewarded||Gems Rewarded|
|Bigger Coffers||Highest Gold Storage level||2/5/10||10/100/1,000||2/5/10|
|Get those Goblins!||Stars gained in the Single Player Campaign||10/50/150||10/100/1,000||5/10/20|
|Bigger & Better||Town Hall level||3/5/8||10/100/1,000||5/10/20|
|Nice and Tidy||Total Obstacles removed||5/50/500||10/100/1,000||5/10/20|
|Release the Beasts||Highest Barracks level||2/5/9||10/100/1,000||5/10/20|
|Gold Grab||Total Gold looted||20,000/1,000,000/100,000,000||10/100/1,000||5/10/20|
|Elixir Escapade||Total Elixir looted||20,000/1,000,000/100,000,000||10/100/1,000||5/10/20|
|Sweet Victory!||Highest Trophies reached||75/750/1,250||10/100/1,000||5/10/450|
|Empire Builder||Clan Castle level||1/2/4||10/100/1,000||5/10/20|
|Wall Buster||Total Walls destroyed in Multiplayer Battles||10/100/2,000||10/100/1,000||5/10/20|
|Humiliator||Total Town Halls destroyed in Multiplayer Battles||10/100/2,000||10/100/1,000||5/10/50|
|Union Buster||Total Builder's Huts destroyed in Multiplayer Battles||25/250/2,500||10/100/1,000||5/10/30|
|Conqueror||Total Multiplayer Battles won||25/250/5,000||10/100/1,000||5/10/20|
|Unbreakable||Total defensive victories in Multiplayer Battles||10/250/5,000||10/100/1,000||5/50/100|
|Friend in Need||Total housing space of troops donated||100/5,000/25,000||10/100/1,000||5/25/250|
|Mortar Mauler||Total Mortars destroyed in Multiplayer Battles||25/500/5,000||10/100/1,000||5/10/20|
|Heroic Heist||Total Dark Elixir looted||20,000/250,000/1,000,000||10/100/1,000||5/10/20|
|League All-Star||Highest Trophy reached||2,000/2,600/3,200||100/500/2,000||250/1,000/2,000|
|X-Bow Exterminator||Total X-Bows destroyed in Multiplayer Battles||1/250/2,500||50/100/1,000||50/100/200|
|Firefighter||Total Inferno Towers destroyed in Multiplayer Battles||10/250/5,000||50/500/5,000||100/200/1,000|
|War Hero||Total stars gained in Clan Wars||10/150/1,000||50/500/5,000||50/200/1,000|
|Treasurer||Total Gold collected from the Treasury||800,000/15,000,000/100,000,000||100/500/5,000||25/100/500|
|Anti-Artillery||Total Eagle Artilleries destroyed in Multiplayer Battles||20/200/2,000||100/800/5,000||150/300/1,000|
|Sharing is Caring||Total housing space of spells donated||100/2,000/10,000||20/200/2,000||20/100/500|
|Keep your village safe||Village linked to Supercell ID?||Yes||100||50|
|Games Champion||Total points scored in Clan Games||10,000/50,000/100,000||20/200/2,000||50/100/250|
|Get those other Goblins!||Stars gained in the Single Player Campaign||175/200/225||200/500/1,000||20/50/100|
|Dragon Slayer||Slain the Giant Dragon?||Yes||200||20|
|War League Legend||Stars gained in Clan War Leagues||20/100/250||200/1,000/2,500||20/100/250|
|Well Seasoned||Points earned in Season Challenges||5,000/15,000/50,000||20/200/2,000||50/100/250|
|Builder Base Achievements|
|Master Engineering||Builder Hall level||3/5/8||20/200/2,000||10/30/50|
|Next Generation Model||Builder Barracks level||2/7/10||20/200/2,000||10/30/50|
|Un-Build It||Total Builder Halls destroyed in Versus Battles||5/100/2,000||20/200/2,000||10/30/50|
|Champion Builder||Highest Versus Trophies reached in Versus Battles||200/1,000/3,000||50/500/5,000||10/100/1,000|
|High Gear||Total buildings geared up with the Master Builder||1/2/3||20/200/2,000||10/30/50|
|Hidden Treasures||Buildings rebuilt in the Builder Base||Gem Mine/Clock Tower/Battle Machine||20/200/2,000||10/30/50|
- Completing all Achievements gives a total of 13,227 Gems and 74,230 Experience, which is enough to buy all five Builder's Huts (with over 9,000 gems left over).
- Completing the entire League All-Star achievement and its prerequisite the Sweet Victory achievement totals 3,715 Gems, which is 215 gems more than the total price of the third, fourth, and fifth Builder's Huts.
- "Hidden Treasures" is the only achievement that you can fulfill the requirements not in the natural order. However, you must complete the first stage to be eligible for the second stage's reward, and so on.
- Although classified as Home Village Achievements, the "Nice and Tidy" and "Games Champion" can be achieved in both villages, while the "Keep Your Village Safe" is not village-specific.
- Most achievements that count cumulative amounts of certain data have identical requirements as some Clan Game Challenges: Nice and Tidy, Gold Grab, Elixir Escapade, Wall Buster, Humiliator, Conqueror, Friend in Need, Mortar Mauler, Heroic Heist, X-Bow Exterminator, Firefighter, War Hero, Anti-Artillery, Sharing is Caring, and Un-Build It.