can someone tell me what am i suppose to do to complete this level coz im going crazy

thanks

I got almost to the end, something about just taking out some more Japanese and then had to go back to the last checkpoint after blowing the first bridge at which time the game screwed up and wouldn't start for more than a second and then I got the restart menu. Now I'm back to the defending the airfield and my rockets seem to have lost their proximity fuses and torpex. I'm not very happy and am ready to go to EB and trade this piece of in.