The film isn't anything original in terms of the story, the film's pacing is hurt mostly by drawn out melodramatic scenes eg when his mother calls him home to tell him about his brother's wedding and the plane scenes. And there is a lot of overacting mostly from Akshay Kumar and other supporting casts. They tend to exaggerate their facial expressions and shout, even though the particular scene requires them not to, which makes the film irritating.
The one thing that I'd to discuss it's the geography the film's set and how the characters behave in it. It's America and people mostly speak English but when Maya or Don are addressing the crowd, they use Hindi which I find to be kinda awkward since they literally don't what they're saying but still cheers to it. And there are also Hindi-speaking police officers in the station which the film features a lot for obvious reason but it's very implausible for that to be the case realistically.
The soundtrack is nice, there are two catchy songs I think, the rest are meh. The sound effects in this type of old Bollywood films never ceases to make me laugh, whenever someone's getting punched, it sounds like they beating a snare drum "buch, gbuch" and same goes with the sound effects of the guns, they're all sound the same no matter the gun type, moreover when someone gets shot, the gunshot wound and blood is practically non-existent.
The cinematography is not bad for its time; the camera-work is good, and able to follow the fight sequences steadily.
Action scenes are well staged but after sometime it gets repetitive especially the one with the Undertaker, at first it's fun but then turns to caricature-like. Moreover, I find the action stunts towards to be far-fetched; like Akshay turning to a tiger? he can literally lift the Undertaker? His wounds come and go only where it's needed? and the special effects are very low-grade.
The highlight of the film is the performances, with the strongest coming from Rekha, she's portrayed her character with such aura of menace that's makes it so memorable, and unique from the rest. Her character is beautiful, and strong and feisty. Akshay Kumar brings energy and enthusiasm to his performance too, and his stunt work is impressive. The rest are so-so in the roles.
Overall, KKK is not a bad film per se, it certainly has many flaws for sure but it offers a tremendous amount of entertainment and good performances.
