The acting is fair enough. The story is lacking though. Like why would Shredder care about making Eric Sacks (William Fichtner) rich ? I guess originally though since William Fichtner was supposed to be playing Shredder.
There was no Erick Sacks to make rich and it was actually Shredder himself who had a diabolical plan to make himself rich. Which just isn't Shredder from the cartoon. Either way he doesn't care about making himself or anyone else rich.
The cartoon series has much better writing and is even a lot more engaging. Copying from the flaw of the original movie and making Splinter a rat who taught himself kung-fu I could have lived without. Him being once human and having a daughter named Karai in the show that Shredder stole and raised as his own. Now that was good stuff.
Karai is in this movie but has no great use. Since she just works for Shredder and fights the turtles here and there. There's nothing too special about her character here.
Another problem of course is the look of the turtles. Mostly due to them being too bulky looking with noses. What turtle has a nose ? The 1990 film was flawed and goofy but better made and a little less stupid.