Although I understand the lower reviews for some of the dialogue or more 'modern' and 'cringe' elements of this movie, I find that like the last animated series for TMNT, this movie is completely and utterly criticized for nothing more than doing something different.
This is a TMNT movie where the turtles finally get to live up to their name; teenagers. As a teenager who grew up on TMNT movies and looked up to them, this movie was so important to me. The uplifing, inspiring theme of "Don't do it for them, do it for you." is so important in our current society and generation.
If you didn't like this movie, or watched it with yearning for the older, more nostalgic adaptations, I urge you to watch it again with an open mind. It is a visual, musical, and encouraging masterpiece that I hope touches so many people as much as it did me.