No other movie has generated much controversy in the history of Indian cinema for the past 50 years or so. Initially bogged down by DTH release, later by ban; Vishwaroopam should be the only movie to have multiple releases (a belated release in its native state). The movie first had a Worldwide release on January 25, 2013, then in North India (Hindi) on February 1, 2013 and followed by Tamilnadu on February 7, 2013. This hampered its collections very badly. Mr. Chandrahassan reported that the delay in release resulted in a loss of around 40-60 crores for Raj Kamal International. An interesting fact is that even though DVD's were freely available in the market prior to its release in Tamilnadu, people were unwilling to watch the movie in DVD's and preferred to watch the movie only at theaters. This clearly shows the respect that people have for Kamal Haasan.
The character of Wisam is a reference to Arjuna in Mahabarath, more specifically the Virata Phase. This is a period in Mahabarath when the Pandavas had to spend their last year in exile in disguise. They live in a different country where they can be recognized. Arjuna takes the guise of a eunuch and teaches dance and song to the girls of the king. This is what exactly Wiz's character does as Vishwanth.
In Wiz/Vishwanath's residence a black two sided statue can be seen. On one side is a king and other side is a queen. In the kathak sequence, the statue is placed against the mirror showing both sides of the statue in the same frame. It represents the role of Wiz in the movie, with double identities: effeminate dancer, and brutal RAW agent.
The Nigerian is shown shaving his hair before preparing for the bomb explosion. This is common practice observed by terrorists of a certain faith, believing that they'll be clean while entering the heaven.
Banned in certain parts of India even after being censored for offending Islamic sentiments by the Tamil Nadu government after protests from a few religious organizations. A couple of days later, an out of court settlement was reached, but by that time it had been illegally downloaded over a million times.