Inception...wow

[Kinzer]

I'm just glad that they didn't try to make to stupid quasi-scientific explanation of how they're able to go into people's dreams. Most other directors would have had some scene where they talk about they reroute the impulses of the brain using super focused radiated unobtanium. Luckily Nolan knows what he is doing.

Also I see your point about the limits of what they can do. I mean it's implied that they can just dream things up, like the grenade launcher, so why not just dream up an APC and some heavy machine guns? Maybe it's like the Matrix, some rules can be bent while others can be broken.