Batman: Return to Arkham - Arkham City

It is hard to guess which maps you will have completed unlocking this achievement. Assuming you go for three medals each time you will get it after 8 maps. You can combine combat maps and predator maps BUT they have to be original maps. Do not go to the bonus maps on the 3rd page.

Personally, I got them after finishing the first 4 combat maps and the first 4 predator maps because these were the only ones I had unlocked at that point. I will put video guides to each of those maps in this solution

Blind justice:

Survival of the fittest:

Rooftop rumble:

Hell's Gate:

Meltdown Mayham:

Police Brutality:

Natural Selection:

End of Line:

(All videos by: Batman Arkham Videos)

Hope this helps you guys!
Any improvements? Please let me know in the comments below!