Teenage Mutant Ninja Turtles is a slightly above average game, at best. You get to play either one of the 4 turtles in a cel-shaded beat-em-up action adventure. While the graphics are quite decent for a cel-shaded game, the gameplay itself is not entirely attractive.
The game itself is not difficult to play, though it does (at times) tend to get a little draggy. The enemies keep coming for you and unfortunately, they do not display all that much AI which is quite unexpected.
Overall, TMNT would appeal to those gamers familiar with the turtles but to those who aren't, there are a host of other games out there which are better.