The car might be his most obvious weakness, so you, as Agent 47, go exploring around that side alley. There is one off-duty cop guarding the car itself, so with a few stealth moves, you take the cop out silently with a stolen knife and stash his body in a dumpster. For a few extra points on your score, you might also take his uniform, just in case you need it later.
With the way clear and your disguise in place, you plant a bomb underneath the car, and once it's all set to blow, bang the hood just hard enough to set the car alarm off. Moving out into the crowds of Chinatown (where vendors peddle their food and a few hundred citizens constantly mill around and wander), you can see your target running back to turn off his car alarm. Unfortunately, he discovers a puddle of blood where you took his hired help out, but it's too late for him: You hit the car bomb and blow the target sky high.
In the ensuing chaos, you casually make your way back through the panicked citizens. With the cops trying to settle the crowd back down, you're able to sneak out a side door, and finish the mission with a respectable, but not great, score.
This time, let's do things differently. You spot the drug dealer ferrying drugs between the target and his apartment. There, an armed guard can be bypassed by sabotaging the security system (and then knocking out the guard when his back is turned).
Once inside the apartment, there are more options: A sniper rifle sits ready by a window, complete with a conspicuous view of your target below. The drug stash is also there: Maybe you can poison the drugs and sneak out in time to have the dealer deliver death for you. There's a gas can full of flammable liquid as well. A distraction, perhaps?
This time, however, you don't do any of those things. Instead, you open the door to the apartment to leave, and run right into the dealer himself. A scuffle ensues, the dealer dies, and then you stuff him unceremoniously in a closet.
With quite a few options already wasted, maybe you can just try the direct approach – walking up to the target and capping him. But even dressed in a cop uniform, the chaos is enough to bring in the SWAT team, and they take you out before you can even start moving for the exit.
Trying to fire the sniper rifle also brings the SWAT team, so that doesn't work. It might from another location.
Poisoning the drugs is a tougher gambit - the dealer's apartment has security cameras running, so it's tough to get in and out quickly enough without being spotted at all. You can destroy the tapes, or even disguise yourself as the dealer, but usually that takes time you don't have.
All of the pieces are there, however. The level is like a finely-made lock, and if you can just line up all of the elements in just the right way, set them out in just the right order and come up with a little luck to boot, you feel like the job can go perfectly. If everything works out, you can accomplish the mission, escape quietly and quickly, and earn the highest score possible.
You try once more, hoping to do things just right for that high score. You wander through the food stalls for a little while, watching the chefs cut and cook, and listening to the workday scuffle of Chinatown. Eventually, you notice a poisonous bit of fish on one of the counters, sitting right next to a female cook carving up the food for the afternoon rush.
It takes a little care, but just when her back is turned, you sneak up and grab the fish with the press of a button. You take a few steps away, and exhale the breath you didn't realize you were holding. No one has spotted you. Yet.
You make your way over to the tiny counter where your target is known to eat, sneak past another busy chef, and surreptitiously insert the poisonous fish into a plate of food on the table without anyone noticing. You wander away again to wait, standing in the crowd, keeping track of the policemen walking by.
A few seconds later, it happens. Your target, gabbing on his cellphone, decides he's hungry, and walks over to the food stand, which he must either own or just visit frequently. As you watch, he takes a bite of his food, and there's a brief moment when you aren't sure if it'll work or not. Was there a bug in the game? Did you do something wrong?
Suddenly, your target convulses and coughs violently. He falls to his knees, and then to the ground, as his guards run from their posts to see what's happening. The UI confirms that you've made the kill without being noticed once. A clean kill that's blamed on a clumsy chef, no extra deaths or loose clues left behind. An assassination, perfectly executed.
With the police ignoring you, you stroll out of the square, silent and victorious. Across the top of your UI, score multipliers and point rewards blossom and burst like Chinese fireworks overhead.