I loved this game!
The graphics were great as was the music and sound effects.
I especially loved that you included difficulty levels (easy was hard enough for me, but satisfying when I beat multiple levels on it). I did notice one small bug: Donatello, died the first two times, but then survived the third, yet at the end it said I had saved him 0 times. Not a big deal - I just wanted you to know.
The story at the beginning was awesome - I just wish it was more integrated into the game and kept moving forward with the fun gameplay.
Overall, excellent!