There is three types of this route:
❶ "All Stop" service, which follows from Brooklyn through Downtown Manhattan to Midtown Manhattan and backward; this servise was described on a separate page «BM2 (Midtown)».
❷ "Midtown Express" service, which follows from Brooklyn to Midtown Manhattan skips stops in Downtown; this servise also was described on a separate page «BM2 (Midtown)».
❸ "Downtown Express" service, which follows from Brooklyn to Downtown Manhattan only and which was described here.
Full information you can see
here.