Your liking of The Lookalike might very well depend on how much coincidences you are ready to accept in a storyline. This one heavily relies on them, some quite extraordinary, but if you are tolerant - or in the mood to be - they are acceptable, especially since they come early on in the introduction of the characters and their respective schemes.
The story is fine, the cast is fine, the picture is often very colourful, in contrast to what must be inside the minds of the protagonists, and there are plenty of beautiful shots, notably of New Orleans and the bayou. What is certainly not so good is the score.
The music is absent from most scenes, but is there for the romance and for the violence. That's unfortunate, specially for the latter. Indeed, these particular scenes lack tension and fail to involve the viewer. Be they a kidnapping or a shoot out, they pass with a level of detachment that doesn't quite fit the genre. I appreciate that they avoid the gruesome of many other films, not so much that they also avoid the thrills. Blaming the music may very well let me overlook other factors, but I'll unfairly leave it at that.