Start the clock as soon as you can control the character end after you shoot the guy in the trunk. The game is split into several different missions on the Weisman Office Building once you've complete the investigation move to the door and walk into it. You will get into the next room before the NPC.

On Burnback alley rush to the guy coming down from the roof and kill him quick and then run to the door (You're not meant to get through this door) If you're quick enough you can open it which bugs out the AI behind it.

Several areas in which its better to just avoid fighting but sometimes its just quicker to kill the enemy than run.

Use shotguns and pistols when available.

Grid 4 is mostly avoiding fighting at the area with the 2 hulks with spades zap the first which blocks the path of the second then head to the ladder before they start coming toward you again.

Processing centre again avoiding most fighting is faster but can be difficult and sometimes you will die doing this.

My video shows most of what is needed to be done per mission but there is definitely room for improvement.

Keep to using quick weapons slow weapons though they do decent damage have terrible blocking which can cause you to die on the higher difficulties.