Shankar Shanmugam the director of 2.0 thinks that if he can make a movie with great VFX then the audience does not need a story and logic. You have Superstar Rajnikanth and a great makeup team for Akshay Kumar which gives a great look of a birdman villain , so you don't need any great explanation for the events happening in the movie.
One thing that stays in your mind after the movie , is the word 'DOT' , Dr. Vassikaran always say the word dot after saying a line which he thinks was so powerful that nobody questions on it. First half is literally irritating, the screen time given to the flying mobiles incident is too long and really gives you a headache with the sound effects used with it, the vibrating sounds mixed with the sound of background score of 'The Inception' after a time forces you to put fingers on your ears. The first half seriously tries to make this movie a comedy horror. Like the way people are being killed by the mobile phones looks dark as well as funny because of that animation of cute little bird moving in the phone. Chitti returns to save people form this destruction but clearly he is not a robot , he is a superhero which has power even more than Superman or any other superhero ever made , he can run fast , he can fly , he can lift up anything but he doesn't have a way to have a extended battery life. He is so advanced but he doesn't have the technology to use solar power to charge himself. Then one things leads to another , Chitti meets Pakshi Ranjan, the birdman who hates cell phones as the radiations emitted from the cell phone newtork towers is apparently killing all the birds. This is one of type of Sci-Fi movie that tells technology is harmful.
Now second half, is a visual spectacle, you can literally feel crores of money spent on almost each and every scene. No wonder it is the most costliest film of India. Some scenes are really funny like the bird made of mobiles dropping the egg and the egg then transforms into Akshay Kumar as Birdman will actually make you laugh while it was meant to be treated seriously. And I don't understand , Pakshi wanted to put a restriction on the radioactivity caused by the network towers but he doesn't understand that people also use Internet provided by network companies on their laptops, computers and tabs. Only cell phones are the target of Pakshi ,I don't know why. Only VFX used in this movie is worth a watch , nothing else. Akshay Kumar is named Pakshi, I have never met a guy with this name ,so no wonder he invested his time in understanding the life of birds. The past story is compelling and really forces you to sympathize with Pakshi but the way of taking revenge is completely wrong and illogical. If a little work was done on a script rather than investing most of the time in VFX , this film could have been marvelous. The stadium fight sequence and the way all the mobile phone assemble to kill a person gives you a visual treat. Cinematography saved this movie from being a total disaster.
Amy Jackson as Nila the robot, does a great job in fulfilling the needs of the character, as Robots generally don't have an expression and Amy does not know how to give one. So you know it is a perfect match. Adill Hussain as the PM of India did a fine job by nodding his head to everything. Sudhanshu Pandey as Dhirendra Bohra played his limited role in a good manner.
Lastly, if you wanna go for this movie only go for the never seen before VFX. Otherwise everything in this movie is 'beyond science' and beyond everything you can ever imagine. While, Rahman's music was very good conditionally but wasn't able to make an impact .
Final Verdict -1/5.
Worth a watch if you are looking for a dark comedy filled with awesome VFX.