Was the Mal in the last scene the projection from Cobb's mind? Because if she died earlier why would the projection want him to stay, also why did she attempt to kill him in that scene too? Also in the last shot it seems like the totem keeps on spinning forever, but then starts shaking more and more, and then they immediately cut to the credits, was this to strike questions in the viewer's minds as is this also yet another dream that Cobb didnt realize he was in? Or did it stop spinning if the credits hadn't cut that scene?

I really liked was near the end, when Fischer was telling "Uncle Peter" (Eames) That he was going to be different from his father, then with a dolly shot around Fischers head to show that "Uncle Peter" was Eames. I loved it even though it was long it kept me into the action and in the scene where the old Saito and Cobb meet for the second time in a dream, I felt it was genius of Christopher Nolan to incorporate that logic into the movie

So, we all know that Cobb promised Mal they'd be together, blah blah blah, right? And we know that projections can properly interact with the dreamers, too, like in Room 528 where they talk to the suposedly evil Browning. Well, Cobb's projection of Mal is only as good as he can imagine her from what he remembers, and so she is built around his memories of her and his relationship with her. Therefore, he imagines that she still wants them to be together, in the dream world. Because of Cobb's uncertainties - you see how he's kinda' addicted to spinning that weird little, uh, spinning top - of what's real and what isn't, which is emphasized by Mal thinking that their world wasn't real, the Mal he has created is based mainly around when she died, when she tried to get Cobb to kill himself aswell, and how she seemed on the verge of madness, but Cobb loves her and wants to be with her all the same.
So Cobb is imagining in Mal's projection that she, the projection, is trying to get him to kill himself, so that he can meet the real Mal in the "real" world. I did suss it out pretty quickly after the first viewing, but if I didn't explain that very well, just say.

And the ending? Very ambiguous, but it's supposed to be.
This is what the script says (yes, I have a copy of the script):

Behind him, on the table, the spinning top is still spinning. And we-

Fade out.

But in the actual film, is starts to rattle, just enough to confuse us. It could right itself and carry on, or it could topple over. We don't know. And if I remember rightly, Christopher Nolan doesn't either. Funny, huh?