Firstly, rather than being a theme song it sounds like a theme piece.
The underlying laidback beat has hip hop flavor with jingle chime effect.
Heroine (Manasvi) goes wacky at 0.40 by sticking her tongue out bindaas, very naughty. Producer aur director ne bol daala karne ko, aur heroine ne kar daala, without any second thoughts on how it will look or portray her. Bollywood ki kuch heroines mein aisa boldness aur daring hai. 
The saxophone piece plays from 0.31 to 0.35, 1.11 to 1.16
The harmonium piece plays from 0.40 to 0.48 along with tabla beats which gives good rhythm. 
The trumpet piece plays from 0.57 to 1.02
The male adlip from 1.08 to 1.11 is hilarious and lol. 
The vibrant metal guitar plays from 1.29 to 1.41
Off-da-hook fast drum roll hits from 1.52 to 1.59 also used in Tandoori Nights and Soniye Je Tere from Karzzz.
Off-da-hook catchy funky guitar riff from 2.01 to 2.03 similarly used at 1.51 & 3.03 in Ye Ladki from Maine Pyaar Kyun Kiya, aong with police siren sound. 
Harmonium piece is back from 2.12 to 2.36
Ideally, one would expect a power packed theme song (like Bodyguard Title Trax) for a masala film in Action genre, but this theme song is quite the contrary and opposite. However, it works and will make the desired impact as promotional prop. Ajay Devgn's husky dialogues, Prabhu Deva's cool dance steps and Manasvi's bombshell looks with killer shiny top  (she outshines Sonakshi completely) will generate attention. The makers opted for a laidback minimalistic theme piece, without all the extra woof woof and boom boom (which was already in Gangster Baby), so that they could showcase the cool dance moves based on Micheal Jackson's style (is it some kind of homage to him) and also create a chill pill setting. 
The choice of beats and instruments in terms of an overall diverse mix is interesting i.e. laidback hip hop beat with jingle chime effect and intermittent  tabla interlude, along with saxophone, harmonium, trumpet, metal guitar, fast drum roll hits, catchy funky guitar riff. 
Best part is from 1.53 onwards, with the combo of off-da-hook fast drum roll hits, harmonium piece, off-da-hook catcy funky guitar riff and police siren sound, whereby Prabhu Deva shows his cool dance moves and flexibility of his body muscles to twist n turn in unconventional ways. 
Prabhu Devas best dance moves are from 0.42 to 0.48, 0.57 to 1.01 & 1.53 onwards. A novice could sprain their ankle while attempting to do the dance step from 2.07 to 2.11
Best instrumental pieces in this theme are harmonium piece from 0.40 to 0.48 & 2.12 to 2.36, off-da-hook catcy funky guitar riff from 2.01 to 2.03 and off-da-hook fast drum roll hits from 1.52 to 1.59 
The overall elegant n classy set, props, backstage and lighting is superb n fab. It has an international feel to it.