A very short and simple guide to 100% the achievements of this game.
How to Obtain All Achievements
The Achievements themselves are fairly simplistic in the fact you need to collect a number of souls to unlock the next one.
There are 26 of them (one for every letter of the alphabet) and go up in 5 soul increments from 5 to 130.
How do you get souls? There is 2 methods:
Kill the skeletons that are attacking you and collect the glowing object they leave behind.
Method 2 (Recommended)
Look for and collect the floating ? in the map, they can give from 5 to 40 souls in my experience and always seems to have one on the map though they do also "Kill all" and give 1 minute of Infinite grenades.
My method to quickly get this done is to ignore the skeletons unless they are in my way and run around the map in a clockwise motion while collecting the floating ?'s on the map. With this method I was able to knock out all the achievements in 5 mins!