First off, kudos to the Malayalam superstars. Dulquer Salmaan (for backing this) and Director Anoop Sathyan for being the master craftsman.
Secondly, how does Kerala's cinema manage to impress us all with simplistic stories and presentation? Especially when they are filmed in Chennai, Tamil Nadu. Tamil films these days (outside of Shankar and Gautham Menon) often show us a grungy feel, often depressing. The presentation shown here makes Chennai look like a million bucks. Even Bollywood has exhaustively shown films set in the gullys of Mumbai/Delhi/Punjab.
Coming to the film itself. The movie could have easily gone off track with the multiple tracks (Nikki-Teacher, Bipeesh-his brother-Akashavani, Unnikrishnan-Teacher, etc.) but everything here is inter-woven so well, you're invested in the proceedings.
There are many standout scenes, especially with Urvashi. Her scenes are a scream and her scenes with Nikki (Kalyani) will likely leave you teary-eyed. Suresh Gopi as the retired Major, Unnikrishnan shows that time hasn't been kind to him, but man when he delivers, he delivers. His speech in the climax is just outstanding. Then there's Shobana (what grace!), KPAC Lalitha (another stealer as the serial artiste and caretaker of Bipeesh and his brother). Enough has been said about Dulquer's efforts, he continues to deliver here, but the MVP is Kalyani Priyadarshan. The scope she didn't get in her previous Tamil film, HERO, she got the right opportunity and scope for performance and she SOARS.
Go watch it. Dear, Tamil filmmakers, you can still make feel-good family entertainers without resorting to bumbling comedians like Soori, Sathish, Rajendran and Yogi Babu adding reels and irritating us. Even a Santosh Subramaniyam (despite being a Telugu remake) is still repeat worthy than say a "Seema Raja" or a "Varthapadatha Valibar Sangam."