There's also a forum topic discussing the puzzles in this game at length on the bigbluecup forum here.
To reach the best ending, you will need to maximize trust of Matt and obtail all three newspaper articles. To do so, your actions will need to include the following:
- Before blasting the door, tell him that you are going to do so.
- Show him the first article.
- As the game progresses, additional dialogue options will be available with Matt. If you choose the polite options, you will gain trust.
- Ask Matt about the Wrench, if you are allowed to keep it.
The three articles:
- The first is in the control room in the prison (or earlier; you need this article to continue with the game.)
- The second is in the crack within the sewer area.
- The third is located in a locker. To open it, you need to pop it open with the wrench while Matt isn't looking.