Scars Above

You gain experience from a few key fights, and picking up objects. Most of your experience will be gained from picking up purple knowledge cubes.

Tier 2 Ability Recon Will allow you to scan for interactive items once you progress far enough to get the pulse scanner, making it easier to find purple knowledge cubes.

You can easily get all abilities in a single play through (I had 11 spare skill points by the end of the game).

The biggest issue with this and many other achievements in this game is that losing your internet connection while playing stops you from being able to collect achievements for that session. So Save your game before purchasing your last skill, and quit the game if you don't get the achievement. In fact it's recommended by a lot of people to save your game at a pillar twice (to make sure it saves properly, I guess?) and then quit the game at the end of every chapter (so you can refresh your game and still get achievements.)

People have also said that if a tier 4 ability is your last purchase, you won't get the achievement. I'm not sure if that is correct or not, but just to be safe, leave a tier 1, 2, or 3 ability for last.

This can happen quite easily in one playthrough. Once you unlock the Recon ability which expands the scanning reach, finding the Knowledge Cubes will be much easier. I unlocked this during Chapter 5, because during Chapter 4 and 5 there is an abundance of Cubes.