X-Men: Destiny
50 Achievements
15-20h
Mechageddon
Defeat 20 Purifier Stalker Mechs.
4.8%
How to unlock the Mechageddon achievement in X-Men: Destiny - Definitive Guide
If you want to grind this achievement, then I recommend accepting Surge's mission within Mission Four. There is always a Purifier Stalker and a U-Man to be fought within, plus a decent amount of Purifier enemies. Once completed you can load up this mission anytime to replay from the load menu after choosing the character you used to unlock it, it should be Challenge Mission #8 with Surge's image on it.
Also, Challenge Mission #11 (Purifier symbol on the image) has a Purifier Stalker within it as well. This challenge can be found in Mission Five "Uncovered" and it should be the second regular open door you come across when you reach the very top of the catwalks. Instead of going left from you come up, make a right into this door.
After fighting twenty of them, the achievement is yours.
Once the game has saved, just quit and restart the mission again.
Purifier Stalker Mechs are the two legged robots that you'll first encounter in Mission 4: Mutant Rescue a few more throughout the story mode and other challenges. Purifier Stalker Mechs only have three main attacks; a machine gun, stomp shockwave and a multiple stomp combo attack. Each of these attacks are easy to read and dodge by either simply jumping or rolling away. In order to defeat Purifier Stalker Mechs you'll have to deal enough damage to its legs until they collapse and expose their weak point. Once their weak point is exposed simply attack it to inflict damage to its health meter before it recovers again. If they do recover simply repeat the damaging their legs process over again until they collapse for you to finish it off. To keep track of all your statistics simply press the button and then .
In order to farm defeats more quickly, simply replay Challenge Mission 8 to defeat 1 Purifier Stalker Mech along with 29 Purifiers and 1 U-Men.