How do i defeat dingo in third mission

First of all, blast the hell out of his shield while you are fighting him. I find the best way to do this is to repeatedly fire while also launching grenades. Eventually, his shield will break, and you will have a very little bit of time. When his shield breaks, go all out!! Use all the bullets and grenades you can as quickly as you can, and you should be able to win.

I would suggest hurling bombs at him and shooting his shield between bomb reloads. I think you can shoot at his head when he pops out from behind his shield to shoot {i THINK}. Once his shield is gone, he is pretty easy. Just fire more bombs and bullets. Even easier with 2 people. It may take a few times but after a couple if tries, he should be relatively easy.