Here's my full summary and review of Batman/TMNT II #6 at TMNT Entity.
Ended how I thought it would, so not much to say. Though really, if anyone should have been carted off to prison at the end, it should've been Donnie for causing all that destruction (and most certainly a number of deaths). Oh, but he felt sorry for his mistake? Well, then that makes everything ok, I guess.
Batman felt incidental half the time in this mini; like if you cut him out completely or substituted him with somebody else, it wouldn't have changed anything.
At least the art was spectacular. I definitely got my money's worth on that end.