Personally, I am not a huge brawler fan but wanted to give it a go because of the nostalgic feelings that Teenage Mutant Ninja Turtles give me.
In that regard, I was not disappointed.
However, without prior knowledge of the franchise, you will not understand what little story the game has, but it is not the focus of the game anyway.

At first glance, all characters seem to be the same and the only difference is their stats (Speed/Range/Strength).
But they all have some differences in their move sets, nothing major, but enough to be noticeable.
After spending time with them all, I got some favorites I had an easier time with than with others.

The base game has two modes: Story & Arcade Mode.
The major difference between these two is mainly how it saves.
You need to play Arcade mode through in one go, while story mode allows you to take a break after each stage.
The Story Mode does not let you change difficulty mid-game, but given that you can finish the game in less than 2 hours, just starting a new run is not much of an issue either.

Apart from soundtracks, there are two DLCs: Radical Reptiles & Dimension Shellshock.
Both of them add two more characters to play.
Dimension Shellshock also adds the Survival Game Mode where you just play until you are dead.

Finding random online lobbies for co-op play or people joining your game if you open it to the public is not a common occurrence anymore.

Let's face it: if you do not like arcade-style brawler games, this game will not convince you all of a sudden.
But if you are, especially if you have a knack for the turtles, you will sure have fun playing the game.