Interesting idea, but there's not enough to it. I'd love to see a Retriever 2 with more variety. Perhaps shooting the cameras slows down the cops, and shooting the bell causes guards to lower their weapons, giving you an opening to shoot first even if they're looking right at you. What I'm saying is maybe design levels that can be beaten in many different ways. Make it interesting, rather than just a basic run 'n gun style mechanic that we've seen too many times.