A relatively generic spot in the list of Jackie Chan movies, but still with its moments if you stick around until the end. It fits in well with his other films from this period (the Police Story and Armour of God films) - stretches of broad comedy where Jackie has to put up with romantic mishaps and troublesome companions, occasionally interrupted with jaw-dropping stunt/fight scenes set in environments with lots of items to throw/dodge/hide behind.
In this one, the gimmick is that there are two Jackie characters - twins separated at birth. One grew up on the streets to become a scammer and a fighter, while the other became a conductor and concert pianist. They inevitably meet up in Hong Kong, where the fighter has just run afoul of some other bad guys, and the conductor has arrived for a concert. The usual set of mistaken identity hijinks ensue, and run far longer than really needed. (I also get a chance here to rant about actors attempting to fake piano playing. It's a hard thing to get to look right, so I don't know why directors think they can just sit an actor in front of a piano and have him massage the keys for a few seconds and have it look good. I give this film a little slack, because it was just a goofy Jackie Chan film, but still - directors, just say no to fake piano playing!)
For whatever reason (maybe because this was a for-charity production), there is really only one big set piece here, occurring at the very end. The two Jackies work together to rescue the useless companion character from the bad guys. However, considering that we had to wait a while to get there, the sequence ends up being well worth the wait. After starting out with cranes at a dock, the action moves into a vehicle test facility, giving Jackie and thugs (and Jackie #2) opportunities to play around with environmental test rooms, vehicle test robots and crash test runners. It's not too dissimilar from the sequence in the airplane test facility in Armour of God 2, and shows off Jackie's (and his stunt team's) talents very well.
I can't really slag this film too hard, just because I did enjoy the last sequence (and because I'm a sucker for Jackie Chan films). But the middle section means this can't get more than a middling three stars.