He is the ultimate assassin, he can be invinsible, he can run at more speed than a normal human being can, he can take loads of bullets, BUT he can't kill a guard who is in fact just a human being!!!
Wow dude, if you don't want to make guards killable, then AT LEAST remove the timer! Seriously, this game is about tactic and patience, and not being in hurry to finish a level.
Make the guards less or make it so you can kill at least some guards, many people want this, not just me. I know he is an assassin and not a murder, I know the difference between those two words, and I also know that some assassins kill what gets in their way even secretly, in that case, the guards.
Seriously, the guards should be killable, people who think this are not missing the point.
It gets on some people's nerves to be losing a level repeatedly by some guards who are many, and still we can do nothing to trim their numbers! Just fix this and make something like 2 kills maximum for guards in a level or 3 plus the green guy.
Life is not simple. It is harder than you think it is.
Well, it is simple enough for someone who takes drugs sometimes, but that way ruins the life.
You have to choose, a short but good life, or a long but good life only if you know how to REALLY enjoy it? Ok, I admit I got this too far. After all this game is a noob game.