Watch it for the VFX - best by Bollywood so far.
The Concept is good but storyline could have been more tighter. Bad dialogues in general, lack of chemistry between leading pair, lack of character development or value of Esha(Alia's character) and trying to make it a love story at the end of it - makes the film naive and suffer a lot - shows the director is still naive.
SRK starts with bad dialogues and cringe worthy acting. Nagarjuna is good. Amitabh Bachchan is good but could have used and given more opportunity to use his Mohabbatein's Gurukul Skills. Ranbir & Alia struggle repeatedly - more together. Mouni Roy is the best of the lot. Rest other characters even though had significant scenes weren't invested upon. End scenes during climax confuse a bit.
Director needs to pull up his socks for part 2 which can be great. Should get better dialogue writer and actors and focus less on love story (something I am afraid might actually happen more of between Amrita & Dev).