This looks amazing. Keep it up!
Wow! Looks like you’re reaching your target 
It can not be deemed finished product. It actually can not be deemed game yet. But work is started. I thought about this idea for a long time and this competition was the impulse to get started. I have still much to do. And I have many ideas for this game.
For example, add some noisy telephoto with limited range. Or a time machine. Or many other things.
If I finish everything as planned, everyone who knows how to use Blender, can easily create new levels for this game.
All that done up to this point, you can download from here: https://yadi.sk/d/qSqa4Ip4gyzvx
Or follow the continuation of work on: https://github.com/Acvarium/BGE_StelthyThief
There you can see how it works:
Very cool! Just spotted a small typo: it should be “the door is unlocked”. Nice game indeed and now you have something to expand on.
Some other things:
-could you make the ai turning smoother? You’re propably using navmesh, which causes the hard turning. You could try to switch to track to actuator for the turn and back to the navmesh after the turn.
-(I guess that’s planned, but please have something happen when you get seen. Like theyattack you or call the cops.
-stop him from walking into the door when using the crowbar.
I fixed text of the message and made animation to stop during unlocking doors.
The rest will be done, but later, when I will have free time again.
New version: https://yadi.sk/d/8kN6O9pZgz4jQ
And new video: