The fight scenes had literally zero energy and were kind of weightless. Considering they bothered to remake it, you'd think they would've spent some money on hiring a decent fight choreographer. Van Damme did it in the original so why not this one?
The choreographer is Larnell Stovall ("Undisputed 3"), who is one of the best in the business. He might not be at fault though, as producers and post-production folks are famous for taking the energy right out of good fight scenes. The director, John Stockwell, did nothing interesting with Gina Carano's fights in "In the Blood" either.
No reviews I've read have said anything indicating the feel of the actual kickboxing, leading me to assume it's not any good. I haven't seen this movie, and I'm not sure I want to, as I thought the fight scenes in the original absolutely sucked, and I've never understood why folks call any of JCVD's early films classics.
Larnell Stovall turned down the 4th "Undisputed" film to work on this one, and that's a damn shame. All the reviews I've read for it (actual title is "Boyka: Undisputed IV") can't stop talking about how good the fight scenes are.
The difference is that the original's fight scenes, while quite slow and not very frantic, were full of energy and impact.
This is due to a good combination of slow motion and some thick sound effects plus the action had some amazing music to back it up. It was all shot in either mid range or wide angles so you could really see what was happening.
This new film does away with all of that and utilises Bourne style quick editing and shakycam which pretty much equates to not being able to see a damn thing and the weak sound effects sound like someone's wrist getting slapped so there's no sense of force to the hits. Chinese director's knew this and that's why all the old films have such OTT sound effects becasue it wasn't just for show or humour.
The fights were obviously choreographed first and then the camera's set up around that whereas in Hong Kong style movies the action is choreographed FOR the camera to make it as dynamic as possible.
It's just a poor film overall. Some bits look like they were shot on a smartphone and it's choppy and kind of annoying all the way through. The only reason it get's half the attention it does is due to it's name and heritage but apart from that it's pretty bland modern style action which is mostly done in post with no real substance.