Who put drugs in the guards coffee?
To complete this game you need 2 parts skill and 369 parts luck!
What could you have done better... well:
The movements of the guards/victim are so random and unpredictable you can't form a plan of attack, you just have to wing it and hope.
Who brings a knife to a gun fight? Only the clinicaly suicidal. Even then you cant use the damn thing to kill the guards, why is that? If it's that you trying not to cause alarm, well that doesnt hold water becuase no matter what you do, they're gona be pretty damned alarmed.
Speaking of alarmed, why the heck are all the guards so edgy? the instant they get a slight glimps of you they're shooting their guns, and running around like lunatics. It's a wonder that the guards havent all killed each other off, becuase there's no way they could tell who their shooting at in the non existant amount of time between seeing you and putting 300 bullets in your hide.
So you got by all the twitchy randomly wandering guards and have finally killed the victim, now you must wait an arbitray amount of time - which is suspended if the guards get alarmed, and boy will they! - before the exit apears in a random location. Which, ofcourse, you cant use whilst the guards are alarmed >.>
And what is the reward for sitting through all 18 levels of this? a message saying "You've completed tha game! Thanks for playing!"... yeah... nice. -_-