This is actually a pretty entertaining and solid film, so I will be brief with any SPOILERS and the like.
The basic plot involves a team of operatives from different countries that are put together to stop a terrorist attempt. They succeed, but one of the villains survives. What follows is his tale of revenge.
To disguise his murders and not draw up suspicion, the man tries to cover them as other ones. For example, he shoots up a liquor store employee as well as one of the Men in order to make it look like a bad robbery. I'm sure that the employee is glad he came in to work today!
The weird one though involves him killing another one of the Men, who now works in a lab. He makes both him and a female employee disrobe before shooting them in the head. Ha! That will make the crime look like...wait, what kind of crime is that supposed to be? Either way, she had nothing to do with anything. Evidently, the man is a firm believer in collateral damage!
Next up, two people who had the misfortune of being in a bad kung-fu hero's path. It's not pretty. Stay tuned...