1. You could always use more health in my opinion.
2. At level 2 it regenerates health fast so I like It because I play chaoticly. In higher difficulties even going ghost mode, this is probably a good one.
1. This will increase your adrenaline, or fatality capabilities. Its nice if you like one shot kills. If you plan on going chaos its good, but i only suggest for the harder difficulties.
1. Increases speed gain a double jump and take less damage or none from falling certain heights.
2. Great ability with a ton of potential, to speed things up, but only use this one, if your going to sacrifice BLINK. The reason being is that blink can get you basically anywhere, but since you can NOT use all skills in one playthrough, you may want to sacrifice blink for something else.
1. For Ghost or silent type players. Use this to have dead enemies turn to ash and make no noise when they die. Great for sneaking.