Kattappanayile Rithwik Roshan is an entertianer that serves its purpose. The film's biggest positive is the rollicking first half where the film has loads of humour content. Much like Amar Akbar Anthony, Nadirshah and team have taken the route of addressing some issues with light humour.
The storyline of the film isn't that fresh or different, but the sequences of the film and their presentation would keep you engaged throughout. The best part is in the fact that the team hasn't resorted to vulgar comedies to tickle your bones. What you get is pure and unadulterated humour. Importantly, family relationships have been given due importance in the film.
Yes, on the flip side the film has some lagging moments in the second half and cliched elements, but that don't affect overall entertainment factor of the product.
If want you want is pure entertainment, your ideal destination would be the theatres playing Kattappanayile Rithwik Roshan. The film has lot of moments for laughter and entertainment is guaranteed.