i voted for TMNT IV, but, in my opinion, it is slightly better than TMNT ii.
My best to worst would be:
TMNT IV
my favorite beat em up. not a button masher, lots of moves, slightly hard, nice music, graphics, you can beat the game without any special moves.
TMNT II
The best on the NES trilogy, i liked this one more than its arcade version. Great music and graphics, probably the best NES game from my childhood (didnt have too many games back then). The
only problem is the difficulty of some of the last stages, and the fact that bosses have a lot of energy and instantly counterattack whatever move you do.
TMNT III
Havent beaten it yet, never knew it existed (until i was aware that there was a 4), and was never able to play it (had it as a ROM but never worked, and also had it on a hacked xbox a cousin gave me, and froze in the first stage). Recently i bought it, but i dont have that much time.
TMNT Hyperston Heist (its just another verion of TMNT IV, but without some cool detail, and i think slightly shorter. also, i dont remember the story, but i think it was more random, intead of just
explaining that the randomness comes from time travelling like the SNES version).
TMNT I
the only good thing i can say about this one is that i feel nice about it just because its hard and i beat it ... 15 years trying