As what happens with most of the so called criminal/suspense/thriller stories where the suspense builds up and the last episode ruins it all. The reasons/logic everything becomes laughable. Knock Knock.. is no exception to that. And that is the only -ve side to take 1pt out of 10 rating.
NOW, let me first really congratulate and appreciate two factors, often goes unnotices for many others. The cinematography.. picturisation is just amazing. Lavasa in Pune is captured so beautifully here. I have been to lavasa multiple times and still it was hard to believe it's from Lavasa. Such a beautiful Camera work and Editing. That was the first thing that kept me glued throughout. Be it scenic angles, portraits or even shots of people taken from outside the glass windows, restaurants.. so amazing and pleasing to eyese.
Second, costumes/outfits are just amazing. Esp Tanya's costumes were out of the way. I'm male and still loved her dresses. Amazing work again.
Third, most of the acting of the cast was definitely above average. Storyline is good and maintains the suspense till i guess 7th or 8th episodes, after which it almost becomes certain who the culprit is. Generally the one who does not have anything to do in story, still is there in almost all episodes and have almost zero doubt. Ending / logic of murders could have been better.
Still, i would recommend a watch of this webseries. First and Second point should get a credit they deserve.